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Line 1: {{task}} A certain childrens game involves starting with a word in a particular category. Each participant in turn says a word, but that word must begin with the final letter of the previous word. Once a word has been given, it cannot be repeated. If an opponent cannot give a word in the category, they fall out of the game. For example, with "animals" as the category, A certain children's game involves starting with a word in a particular category.   Each participant in turn says a word, but that word must begin with the final letter of the previous word.   Once a word has been given, it cannot be repeated.   If an opponent cannot give a word in the category, they fall out of the game. ~~<pre>Child 1: dog~~ For example, with   "animals"   as the category, <pre> Child 1: dog Child 2: goldfish Child 1: hippopotamus Line 9 ⟶ 13: </pre> ~~;Task Description~~ Take the following selection of 70 English Pokemon names (extracted from [[wp:List of Pokémon\|Wikipedia's list of Pokemon]]) and generate the/a sequence with the highest possible number of Pokemon names where the subsequent name starts with the final letter of the preceding name. No Pokemon name is to be repeated. ;Task: ~~<pre>audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon~~ Take the following selection of 70 English Pokemon names   (extracted from   [[wp:List of Pokémon\|Wikipedia's list of Pokemon]])   and generate the/a sequence with the highest possible number of Pokemon names where the subsequent name starts with the final letter of the preceding name. No Pokemon name is to be repeated. <pre> audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan Line 19 ⟶ 27: porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask~~</pre>~~ </pre> Extra brownie points for dealing with the full list of   646   names. <br><br> =={{header\|11l}}== {{trans\|Python}} <syntaxhighlight lang="11l">F order_words(words) DefaultDict[Char, Set[String]] byfirst L(word) words byfirst[word[0]].add(word) R byfirst F linkfirst(&byfirst; sofar) assert(!sofar.empty) V chmatch = sofar.last.last V options = byfirst[chmatch] - Set(sofar) I options.empty R sofar E V alternatives = options.map(word -> linkfirst(&@byfirst, @sofar [+] [word])) R max(alternatives, key' s -> s.len) F llfl(words) V byfirst = order_words(words) R max((words.map(word -> linkfirst(&@byfirst, [word]))), key' s -> s.len) V pokemon_str = ‘audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask’ V pokemon = pokemon_str.split((‘ ’, "\n")) V l = llfl(pokemon) L(i) (0 .< l.len).step(8) print(l[i .< i + 8].join(‘ ’)) print(l.len)</syntaxhighlight> {{out}} <pre> machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino 23 </pre> =={{header\|Ada}}== <syntaxhighlight lang="ada">with Ada.Containers.Indefinite_Vectors, Ada.Text_IO; procedure Lalefile is package Word_Vec is new Ada.Containers.Indefinite_Vectors (Index_Type => Positive, Element_Type => String); use type Word_Vec.Vector, Ada.Containers.Count_Type; type Words_Type is array (Character) of Word_Vec.Vector; procedure Read(Words: out Words_Type) is F: Ada.Text_IO.File_Type; begin Ada.Text_IO.Open(File => F, Name => "pokemon70.txt", Mode => Ada.Text_IO.In_File); loop declare Word: String := Ada.Text_IO.Get_Line(F); begin exit when Word = ""; Words(Word(Word'First)).Append(Word); end; end loop; exception when Ada.Text_IO.End_Error => null; end Read; procedure Write (List: Word_Vec.Vector; Prefix: String := " ") is Copy: Word_Vec.Vector := List; begin loop exit when Copy.Is_Empty; Ada.Text_IO.Put_Line(Prefix & Copy.First_Element); Copy.Delete_First; end loop; end Write; function Run(Start: Character; Words: Words_Type) return Word_Vec.Vector is Result: Word_Vec.Vector := Word_Vec.Empty_Vector; begin for I in Words(Start).First_Index .. Words(Start).Last_Index loop declare Word: String := Words(Start).Element(I); Dupl: Words_Type := Words; Alternative : Word_Vec.Vector; begin Dupl(Start).Delete(I); Alternative := Word & Run(Word(Word'Last), Dupl); if Alternative.Length > Result.Length then Result := Alternative; end if; end; end loop; return Result; end Run; W: Words_Type; A_Vector: Word_Vec.Vector; Best: Word_Vec.Vector := Word_Vec.Empty_Vector; begin Read(W); Ada.Text_IO.Put("Processing "); for Ch in Character range 'a' .. 'z' loop Ada.Text_IO.Put(Ch & ", "); A_Vector := Run(Ch, W); if A_Vector.Length > Best.Length then Best := A_Vector; end if; end loop; Ada.Text_IO.New_Line; Ada.Text_IO.Put_Line("Length of longest Path:" & Integer'Image(Integer(Best.Length))); Ada.Text_IO.Put_Line("One such path:"); Write(Best); end Lalefile;</syntaxhighlight> Output:<pre>Processing a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, Length of longest Path: 23 One such path: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino</pre> =={{header\|BaCon}}== Naive implementation showing the algorithm. <syntaxhighlight lang="freebasic">all$ = "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon " \ "cresselia croagunk darmanitan deino emboar emolga exeggcute gabite " \ "girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan " \ "kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine " \ "nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 " \ "porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking " \ "sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko " \ "tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask" SUB check(list$, rest$) LOCAL x FOR x = 1 TO AMOUNT(rest$) IF RIGHT$(list$, 1) = LEFT$(TOKEN$(rest$, x), 1) THEN check(APPEND$(list$, 0, TOKEN$(rest$, x)), DEL$(rest$, x)) NEXT IF AMOUNT(list$) > total THEN total = AMOUNT(list$) result$ = list$ END IF END SUB FOR z = 1 TO AMOUNT(all$) CALL check(TOKEN$(all$, z), DEL$(all$,z)) NEXT PRINT total, ": ", result$ PRINT NL$, "Speed: ", TIMER, " msecs."</syntaxhighlight> {{out}} <pre> 23: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino Speed: 662734 msecs. </pre> Optimized implementation. The idea is to quantify the equations. <syntaxhighlight lang="freebasic">all$ = "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon " \ "cresselia croagunk darmanitan deino emboar emolga exeggcute gabite " \ "girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan " \ "kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine " \ "nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 " \ "porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking " \ "sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko " \ "tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask" SPLIT all$ TO name$ SIZE MaxSize DECLARE start, end, used, result ARRAY MaxSize FOR y = 0 TO MaxSize-1 start[y] = ASC(LEFT$(name$[y], 1)) end[y] = ASC(RIGHT$(name$[y], 1)) used[y] = -1 NEXT FOR i = 0 TO MaxSize-1 used[i] = 0 CALL check(used, i, 1) used[i] = -1 NEXT PRINT maxtotal, ": "; FOR a = 0 TO maxtotal-1 FOR y = 0 TO MaxSize-1 IF result[y] = a THEN PRINT name$[y]," "; NEXT NEXT PRINT NL$, "Speed: ", TIMER, " msecs." SUB check(ya[], ultim, nr) LOCAL x FOR x = 0 TO MaxSize-1 IF end[ultim] = start[x] AND ya[x] = -1 THEN ya[x] = nr CALL check(ya, x, nr+1) ya[x] = -1 END IF IF nr > maxtotal THEN maxtotal = nr OPTION MEMTYPE long COPY ya TO result SIZE MaxSize END IF NEXT END SUB </syntaxhighlight> {{out}} <pre> 23: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino Speed: 818 msecs. </pre> =={{header\|BASIC256}}== <syntaxhighlight lang="basic256">dim names$(1) names$ = { "audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask" } global names$, lnames, index, maxlen, first, last maxlen = 0 lnames = names$[?]-1 dim index(names$[?]) dim first(names$[?]) dim last(names$[?]) for t = 0 to lnames index[t] = t last[t] = asc(right(names$[t],1)) first[t] = asc(left(names$[t],1)) next t # try each name as the first name on the list for t = 0 to lnames call swapindex(0,t) call downlevel(1) call swapindex(0,t) next t end subroutine downlevel(lev) #print n$[?] + " " + lev if lev <= lnames then for t = lev to lnames if last[index[lev-1]] = first[index[t]] then call swapindex(lev,t) if lev >= maxlen then maxlen = lev call showsolution(lev) end if call downlevel(lev+1) call swapindex(lev,t) end if next t end if end subroutine subroutine showsolution(l) print l+1; for t = 0 to l print " " + names$[index[t]]; next t print end subroutine subroutine swapindex(a, b) # swap element a and bin in the array index (used to swap names$) t = index[a] index[a] = index[b] index[b] = t end subroutine </syntaxhighlight> Output: <pre>2 bagon nosepass 3 bagon nosepass sableye 4 bagon nosepass sableye emboar 5 bagon nosepass sableye emboar registeel ... 23 machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite exeggcute emolga audino 23 machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar registeel landorus simisear relicanth haxorus seaking girafarig gabite emolga audino 23 machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino</pre> =={{header\|BBC BASIC}}== {{works with\|BBC BASIC for Windows}} <syntaxhighlight lang="bbcbasic"> DIM names$(69) names$() = "audino", "bagon", "baltoy", "banette", \ \ "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", \ \ "cresselia", "croagunk", "darmanitan", "deino", "emboar", \ \ "emolga", "exeggcute", "gabite", "girafarig", "gulpin", \ \ "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", \ \ "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", \ \ "loudred", "lumineon", "lunatone", "machamp", "magnezone", \ \ "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", \ \ "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", \ \ "registeel", "relicanth", "remoraid", "rufflet", "sableye", \ \ "scolipede", "scrafty", "seaking", "sealeo", "silcoon", \ \ "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", \ \ "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", \ \ "wailord", "wartortle", "whismur", "wingull", "yamask" maxPathLength% = 0 maxPathLengthCount% = 0 maxPathExample$ = "" FOR i% = 0 TO DIM(names$(),1) SWAP names$(0), names$(i%) PROClastfirst(names$(), 1) SWAP names$(0), names$(i%) NEXT PRINT "Maximum length = " ; maxPathLength% PRINT "Number of solutions with that length = " ; maxPathLengthCount% PRINT "One such solution: " ' maxPathExample$ END DEF PROClastfirst(names$(), offset%) LOCAL i%, l% IF offset% > maxPathLength% THEN maxPathLength% = offset% maxPathLengthCount% = 1 ELSE IF offset% = maxPathLength% THEN; maxPathLengthCount% += 1 maxPathExample$ = "" FOR i% = 0 TO offset%-1 maxPathExample$ += names$(i%) + CHR$13 + CHR$10 NEXT ENDIF l% = ASCRIGHT$(names$(offset% - 1)) FOR i% = offset% TO DIM(names$(),1) IF ASCnames$(i%) = l% THEN SWAP names$(i%), names$(offset%) PROClastfirst(names$(), offset%+1) SWAP names$(i%), names$(offset%) ENDIF NEXT ENDPROC</syntaxhighlight> '''Output:''' <pre> Maximum length = 23 Number of solutions with that length = 1248 One such solution: machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> =={{header\|Bracmat}}== ===Naive=== <syntaxhighlight lang="bracmat">( audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask : ?names & 0:?max & :?sequence & ( lalefile = done todo A M Z Length first . !arg:(!done.)&!done:?sequence \| !arg:(.?todo) & ( !todo : ?A %@?M (?Z&lalefile$(!M.!A !Z)&~) \| ) \| !arg:(@(%:? @?first) ?:?done.?todo) & :?M & ( !todo : ?A @(%:!first ?:?M) ( ?Z & lalefile$(!M !done.!A !Z) & ~ ) \| !M: & !done:? [?Length & !Length:>!max:?max & !done:?sequence \| ) ) & lalefile$(.!names) & out$("Length:" !max "Sequence:" !sequence) );</syntaxhighlight> Output (read from bottom to top): <pre> Length: 23 Sequence: audino emolga exeggcute gabite girafarig seaking haxorus trapinch rufflet heatmor relicanth simisear nosepass darmanitan loudred registeel emboar kricketune yamask scrafty landorus petilil machamp</pre> ===Optimized=== Optimizations: The <code>whl</code> loop transforms the flat list of names to, conceptually, a search tree with nodes at three levels. The lowest level contains the names. The top level contains the word's first letter and the second level contains its last letter. Words starting with a specific letter are all children of one single top node, speeding up search for candidates. Under a second level node all words have the same letter at the start and the same letter at the end. When looking for candidates it always suffices to take the first word and ignore the rest. This optimization eliminates all solutions that merely are the result of swapping pairs of words with the same begin and end. Notice that the tree is built using the 'smart' binary operators <code></code>, <code>^</code>, <code>+</code> and <code>\L</code> (logarithm). Bracmat uses the commutative, distributive and associative laws to transform expressions containing these operators to canonical forms that fit the requiremens of the search tree. For example, the words in the list <code>sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue</code> end up in this tree: <pre> s ^ ( (.e)\L(sableyescolipede) + (.g)\Lseaking + (.k)\Lspoink + (.n)\Lsilcoon + (.o)\Lsealeo + (.r)\Lsimisear + (.x)\Lsnorlax + (.y)\L(scraftysnivystarly) ) * t ^ ( (.a)\Ltirtouga + (.e)\Ltyrogue + (.h)\Ltrapinch + (.o)\Ltreecko )</pre> Another, less important, optimization is the way in which the last letter of a name is found, using the position pattern <code>[</code> rather than the pattern that matches at most one letter, <code>@</code>. The optimized version is about 4.5 times faster than the naive version. <syntaxhighlight lang="bracmat">( audino bagon baltoy banette bidoof braviary bronzor ~~Extra brownie points for dealing with the full list of 646 names.~~ carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask : ?names & 1:?newnames & whl ' ( !names:@(%?name:%@?first ? @?last) ?names & !first^(.!last)\L!name!newnames:?newnames ) & !newnames:?names & 0:?max & :?sequence & ( lalefile = done todo A M Z Length first , Ms a z last candidates . !arg:(!done.)&!done:?sequence \| !arg:(.?todo) & ( !todo : ?A %?first^?candidates * ( ?Z & !candidates : ?a + ?last\L(%?M?Ms) + ( ?z & lalefile$(!M.!A!first^(!a+!last\L!Ms+!z)!Z) & ~ ) ) \| ) \| !arg:(@(%:? [-2 ?first) ?:?done.?todo) & :?M & ( !todo:?A!first^%?candidates?Z & !candidates : ?a + ?last\L(%?M?Ms) + ( ?z & lalefile $ (!M !done.!A!first^(!a+!last\L!Ms+!z)!Z) & ~ ) \| !M: & !done:? [?Length & !Length:>!max:?max & !done:?sequence \| ) ) & lalefile$(.!names) & out$("Length:" !max "Sequence:" !sequence) );</syntaxhighlight> Output (read from bottom to top): <pre> Length: 23 Sequence: audino emolga kricketune yamask scrafty haxorus trapinch rufflet simisear landorus registeel heatmor relicanth emboar exeggcute gabite girafarig seaking nosepass darmanitan loudred petilil machamp</pre> =={{header\|C}}== From the D version. <~~lang~~syntaxhighlight lang="c">#include <stdlib.h> #include <string.h> #include <stdio.h> Line 43 ⟶ 648: size_t n_solutions; const char longest_path; size_t longest_path_len; /// tally statistics void search(~~const~~ size_t curr_len) { if (curr_len == longest_path_refs_len) { n_solutions++; Line 58 ⟶ 663: // recursive search ~~const~~ intptr_t last_char = refs[curr_len - 1].last_char; for (size_t i = curr_len; i < refs_len; i++) if (refs[i].first_char == last_char) { ~~const~~ Ref aux = refs[curr_len]; refs[curr_len] = refs[i]; refs[i] = aux; Line 70 ⟶ 675: } void find_longest_chain(const char const items[], ~~const~~ size_t items_len) { refs_len = items_len; refs = calloc(refs_len, sizeof(Ref)); Line 80 ⟶ 685: for (size_t i = 0; i < items_len; i++) { ~~const~~ size_t itemsi_len = strlen(items[i]); if (itemsi_len <= 1) exit(1); Line 90 ⟶ 695: // try each item as possible start for (size_t i = 0; i < items_len; i++) { ~~const~~ Ref aux = refs[0]; refs[0] = refs[i]; refs[i] = aux; Line 99 ⟶ 704: longest_path_len = longest_path_refs_len; longest_path = calloc(longest_path_len, sizeof(const char)); for (size_t i = 0; i < longest_path_len; i++) longest_path[i] = items[longest_path_refs[i].index]; Line 108 ⟶ 713: int main() { const char pokemon[] = {"audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", Line 122 ⟶ 727: "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"}; ~~const~~ size_t pokemon_len = sizeof(pokemon) / sizeof(pokemon[0]); find_longest_chain(pokemon, pokemon_len); Line 138 ⟶ 743: return 0; }</~~lang~~syntaxhighlight> Output: <pre>Maximum path length: 23 Line 151 ⟶ 756: ===Approximate=== For dealing with full list (646 names), here's an approximate method. Names are restricted to begin and end with a lower case letter, so for example in my input file "porygon2" is written as "porygon-two". It finds some chains with 300-odd length for 646 names, and found a chain with 23 for the 70 names (by luck, that is), and since it's basically a one-pass method, running time is next to none. C99 code. <~~lang~~syntaxhighlight lang="c">#include <stdio.h> #include <stdlib.h> #include <string.h> Line 346 ⟶ 951: printf("longest found: %d\n", best); return 0; }</~~lang~~syntaxhighlight>output<syntaxhighlight lang="text">read 646 names 307: voltorb breloom magikarp palpito... 308: voltorb bayleef forretress swinub b... Line 354 ⟶ 959: 322: voltorb beldum mandibuzz zekrom murk... 323: voltorb breloom mandibuzz zekr... longest found: 323</~~lang~~syntaxhighlight> =={{header\|DC sharp}}== <syntaxhighlight lang="csharp">using System; ~~Improved from the Go version:~~ using System.Collections.Generic; ~~<lang d>import std.stdio,std.algorithm,std.string,std.range,std.typecons;~~ using System.Linq; using System.Text; namespace ConsoleApplication1 ~~Tuple!(string[], int) findLongestChain(string[] items) {~~ { ~~string[] longestPath;~~ ~~int~~class ~~nSolutions;~~Program { static void Main(string[] args) { string pokemon_names = @"audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask"; string[] pokemon = pokemon_names.Split(new char[]{' ','\n'}); ~~void search(in int currLen) {~~ List<string> chain = new List<string>(pokemon.Length); ~~if (currLen == longestPath.length) {~~ ~~nSolutions++;~~ } ~~else~~ if for (~~currLen~~int >i ~~longestPath~~= 0; i < pokemon.~~length)~~Length; {i++) ~~nSolutions = 1;~~{ ~~longestPath~~ = ~~items~~ swap(ref pokemon[0], ..ref ~~currLen~~pokemon[i]~~.dup~~); Search( pokemon, chain, 1 ); swap(ref pokemon[0], ref pokemon[i]); } foreach (string s in chain) Console.WriteLine(s); Console.ReadKey(); } static void Search(string[] pokemon, List<string> longest_chain, int len ) ~~// recursive search~~ { ~~const dchar lastChar = items[currLen - 1][$ - 1];~~ ~~foreach~~ ~~(i;~~ ~~currLen~~ .. ~~items~~if (len > longest_chain.~~length~~Count) ~~if (items[i][0] == lastChar)~~ { ~~swap~~longest_chain.Clear(~~items[currLen], items[i]~~); ~~search~~for (~~currLen~~int +i 1)= 0; i < len; i++) ~~swap(items[currLen],~~ ~~items~~ longest_chain.Add(pokemon[i]); } char lastchar = pokemon[len - 1][pokemon[len-1].Length - 1]; for (int i = len; i < pokemon.Length; i++) { if (pokemon[i][0] == lastchar) { swap(ref pokemon[i], ref pokemon[len]); Search(pokemon, longest_chain, len + 1); swap(ref pokemon[i], ref pokemon[len]); } } } static void swap(ref string s1, ref string s2) { string tmp = s1; s1 = s2; s2 = tmp; } } }</syntaxhighlight><pre>machamp petilil landorus sableye emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus scrafty yamask kricketune exeggcute emolga audino</pre> =={{header\|C++}}== ~~// try each item as possible start~~ <syntaxhighlight lang="cpp">#include <iostream> ~~foreach (i; 0 .. items.length) {~~ #include <string> ~~swap(items[0], items[i]);~~ #include <vector> ~~search(1);~~ ~~swap(items[0], items[i]);~~ struct last_letter_first_letter { size_t max_path_length = 0; size_t max_path_length_count = 0; std::vector<std::string> max_path_example; void search(std::vector<std::string>& names, size_t offset) { if (offset > max_path_length) { max_path_length = offset; max_path_length_count = 1; max_path_example.assign(names.begin(), names.begin() + offset); } else if (offset == max_path_length) { ++max_path_length_count; } char last_letter = names[offset - 1].back(); for (size_t i = offset, n = names.size(); i < n; ++i) { if (names[i][0] == last_letter) { names[i].swap(names[offset]); search(names, offset + 1); names[i].swap(names[offset]); } } } void find_longest_chain(std::vector<std::string>& names) { ~~return tuple(longestPath, nSolutions);~~ max_path_length = 0; max_path_length_count = 0; max_path_example.clear(); for (size_t i = 0, n = names.size(); i < n; ++i) { names[i].swap(names[0]); search(names, 1); names[i].swap(names[0]); } } }; int main() { std::vector<std::string> names{"audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"}; last_letter_first_letter solver; solver.find_longest_chain(names); std::cout << "Maximum path length: " << solver.max_path_length << '\n'; std::cout << "Paths of that length: " << solver.max_path_length_count << '\n'; std::cout << "Example path of that length:\n "; for (size_t i = 0, n = solver.max_path_example.size(); i < n; ++i) { if (i > 0 && i % 7 == 0) std::cout << "\n "; else if (i > 0) std::cout << ' '; std::cout << solver.max_path_example[i]; } std::cout << '\n'; }</syntaxhighlight> {{out}} <pre> Maximum path length: 23 Paths of that length: 1248 Example path of that length: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino </pre> =={{header\|Clojure}}== <syntaxhighlight lang="clojure">(ns rosetta-code.last-letter-first-letter (:require clojure.string)) (defn by-first-letter "Returns a map from letters to a set of words that start with that letter" [words] (into {} (map (fn [[k v]] [k (set v)])) (group-by first words))) (defn longest-path-from "Find a longest path starting at word, using only words-by-first-letter for successive words. Returns a pair of [length list-of-words] to describe the path." [word words-by-first-letter] (let [words-without-word (update words-by-first-letter (first word) disj word) next-words (words-without-word (last word))] (if (empty? next-words) [1 [word]] (let [sub-paths (map #(longest-path-from % words-without-word) next-words) [length words-of-path] (apply max-key first sub-paths)] [(inc length) (cons word words-of-path)])))) (defn longest-word-chain "Find a longest path among the words in word-list, by performing a longest path search starting at each word in the list." [word-list] (let [words-by-letter (by-first-letter word-list)] (apply max-key first (pmap #(longest-path-from % words-by-letter) word-list)))) (defn word-list-from-file [file-name] (let [contents (slurp file-name) words (clojure.string/split contents #"[ \n]")] (filter #(not (empty? %)) words))) (time (longest-word-chain (word-list-from-file "pokemon.txt")))</syntaxhighlight> Evaluating the last line: <syntaxhighlight lang="clojure">"Elapsed time: 2867.337816 msecs" [23 ("machamp" "pinsir" "relicanth" "heatmor" "registeel" "landorus" "seaking" "girafarig" "gabite" "exeggcute" "emboar" "rufflet" "trapinch" "haxorus" "simisear" "remoraid" "darmanitan" "nosepass" "scrafty" "yamask" "kricketune" "emolga" "audino")]</syntaxhighlight> It initially ran in about 5 seconds, then I changed <code>map</code> to <code>pmap</code> (parallel map) in <code>longest-word-chain</code>. This gave a nice speedup for a dual core laptop; the speedup for parallel searches was over 3x on a server. =={{header\|Common Lisp}}== Pretty brute force here. Takes a couple of seconds to run. <syntaxhighlight lang="lisp">;;; return all the words that start with an initial letter (defun filter-with-init (words init) (remove-if-not (lambda (word) (eql init (aref word 0))) words)) ;;; produce a hash table whose key is the initial letter of a word and whose value is ;;; a list of the words that start with that initial letter (defun group-by-first-letter (words) (let ((map_letters (make-hash-table)) (inits (remove-duplicates (mapcar (lambda (word) (aref word 0)) words)))) (dolist (init inits map_letters) (setf (gethash init map_letters) (filter-with-init words init))) )) ;;; Get the last letter in a word or array (defun last-element (array) (aref array (- (length array) 1))) ;;; Produce a hash table whose key is a word and whose value is a list of the ;;; words that can follow that word (defun get-followers (words) (let ((map-word-to-followers (make-hash-table :test 'equal)) (init_hash (group-by-first-letter words))) (dolist (word words map-word-to-followers) (setf (gethash word map-word-to-followers) (gethash (last-element word) init_hash))))) ;;; Retrieve all the keys from a hash table (defun keys (hashtbl) (let ((allkeys ())) (maphash #'(lambda (key val) (setf allkeys (cons key allkeys))) hashtbl) allkeys)) ;;; Find the words which can follow a word and haven't been used yet. The parameters are: ;;; word - word being tested ;;; followers - the hash table returned from get-followers ;;; available - hash table with word as key and boolean indicating whether that word ;;; has been used previously as value (defun get-available-followers (word followers available) (if (null word) (keys followers) (remove-if-not #'(lambda (word) (gethash word available)) (gethash word followers)))) ;;; Find the best in a list using an arbitrary test (defun best (lst test) (let ((top (car lst))) (do ((rest (cdr lst) (cdr rest))) ((null rest) top) (if (funcall test (car rest) top) (setf top (car rest)))))) ;;; Find the best path in a list (defun best-list-path (paths) (best paths #'(lambda (path1 path2) (> (length path1) (length path2))))) ;;; Find the best path given all the supporting information we need (defun best-path-from-available (word followers available depth path available-followers) (let ((results (mapcar #'(lambda (new-word) (dfs-recurse new-word followers available (+ 1 depth) (cons word path))) available-followers))) (best-list-path results))) ;;; Recurse to find the best available path - the meat of the algorithm (defun dfs-recurse (word followers available depth path) (let ((ret)) ; Mark the word as unavailable (setf (gethash word available) nil) ; Find the longest path starting with word (let ((available-followers (get-available-followers word followers available))) (setf ret (if (null available-followers) (cons word path) (best-path-from-available word followers available depth path available-followers)))) ; Mark the word as available again (setf (gethash word available) t) ; Return our longest path ret)) ;;; Create the availability table (defun make-available-table (words) (let ((available (make-hash-table))) (dolist (word words available) (setf (gethash word available) t)))) ;;; Find the best path for a set of words (defun best-path (words) (let ((followers (get-followers words)) (available (make-available-table words))) (cdr (reverse (dfs-recurse nil followers available 0 nil))))) ;;; set up the words as a set of strings (setf words (mapcar #'symbol-name '(audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask))) (setf path (best-path words))</syntaxhighlight> Output:<syntaxhighlight lang="text">("MACHAMP" "PETILIL" "LANDORUS" "SCRAFTY" "YAMASK" "KRICKETUNE" "EMBOAR" "REGISTEEL" "LOUDRED" "DARMANITAN" "NOSEPASS" "SIMISEAR" "RELICANTH" "HEATMOR" "RUFFLET" "TRAPINCH" "HAXORUS" "SEAKING" "GIRAFARIG" "GABITE" "EXEGGCUTE" "EMOLGA" "AUDINO")</syntaxhighlight> =={{header\|D}}== ===Simple Version=== Modified from the Go version: <syntaxhighlight lang="d">import std.stdio, std.algorithm, std.string; void trySwap(string[] items, ref string item, in size_t len, ref string[] longest) pure nothrow @safe { swap(items[len], item); search(items, len + 1, longest); swap(items[len], item); } void search(string[] items, in size_t len, ref string[] longest) pure nothrow @safe { if (len > longest.length) longest = items[0 .. len].dup; immutable lastChar = items[len - 1][$ - 1]; foreach (ref item; items[len .. $]) if (item[0] == lastChar) trySwap(items, item, len, longest); } void main() @safe { auto pokemon = "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino Line 403 ⟶ 1,353: scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask"~~.tolower()~~.split(); string[] solution; ~~// remove duplicates~~ ~~pokemon.length~~foreach ~~-= copy~~(~~uniq(pokemon.sort()),~~ref name; pokemon)~~.length;~~ trySwap(pokemon, name, 0, solution); writefln("%-(%s\n%)", solution); ~~auto sol_nsol = findLongestChain(pokemon);~~ }</syntaxhighlight> ~~writeln("Maximum path length: ", sol_nsol[0].length);~~ ~~writeln("Paths of that length: ", sol_nsol[1]);~~ ~~writeln("Example path of that length:");~~ ~~foreach (i; iota(0, cast(int)sol_nsol[0].length, 7))~~ ~~writeln(" ", sol_nsol[0][i .. min(i+7, $)].join(" "));~~ ~~}</lang>~~ Output: <pre>machamp ~~<pre>Maximum path length: 23~~ petilil ~~Paths of that length: 1248~~ landorus ~~Example path of that length:~~ scrafty ~~machamp petilil landorus scrafty yamask kricketune emboar~~ yamask ~~registeel loudred darmanitan nosepass simisear relicanth heatmor~~ kricketune ~~rufflet trapinch haxorus seaking girafarig gabite exeggcute~~ emboar ~~emolga audino</pre>~~ registeel ~~Runtime: about 1.23 seconds, dmd compiler.~~ loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino</pre> The run-time is about 0.9 seconds with the dmd compiler and about 0.55 seconds with the ldc2 compiler. ===Improved Version=== ~~A more optimized solution (same output):~~ With two small changes the code gets faster. Here the names are represented as in C (so swapping them means just swapping a pointer, instead of swapping a pointer+length as before), and during the computation their last char is swapped with their second char (so there's no need to keep the string lengths around or use strlen). ~~<lang d>import std.stdio, std.algorithm, std.string,~~ <syntaxhighlight lang="d">import std.stdio, std.algorithm, std.string, std.array, std.conv; ~~std.range, std.typecons;~~ void search(immutable(char)[] items, in int len, ref immutable(char)[] longest) pure { if (len > longest.length) longest = items[0 .. len].dup; immutable lastChar = items[len - 1][1]; foreach (ref item; items[len .. $]) if (item[0] == lastChar) { swap(items[len], item); search(items, len + 1, longest); swap(items[len], item); } } void main() { ~~alias Tuple!(string, "word", bool, "unused") Pair;~~ static immutable(char)* prep(in string s) pure { ~~int nSolutions;~~ assert(s.length > 1); auto sd = s.dup; swap(sd[1], sd[$ - 1]); return sd.toStringz; } static string unprep(immutable(char)* sd) pure { auto ms = sd.to!(char[]); swap(ms[1], ms[$ - 1]); return ms; } auto pokemon = "audino bagon baltoy banette bidoof braviary ~~void search(Pair[][] sequences, size_t minHead, string currWord,~~ bronzor carracosta charmeleon cresselia croagunk darmanitan deino ~~string[] currentPath, size_t currentPathLen,~~ emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor ~~ref string[] longestPath) {~~ heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask".split.map!prep.array; immutable(char)[] solution; ~~currentPath[currentPathLen] = currWord;~~ foreach (ref name; pokemon) { ~~currentPathLen++;~~ swap(pokemon[0], name); search(pokemon, 1, solution); ~~if (currentPathLen == longestPath.length) {~~ ~~nSolutions++~~swap(pokemon[0], name); ~~} else if (currentPathLen > longestPath.length) {~~ ~~nSolutions = 1;~~ ~~longestPath = currentPath[0 .. currentPathLen].dup;~~ } writefln("%-(%s\n%)", solution.map!unprep); ~~// recursive search~~ }</syntaxhighlight> ~~size_t lastCharIndex = currWord[$ - 1] - minHead;~~ ~~if (lastCharIndex < sequences.length)~~ ~~foreach (ref pair; sequences[lastCharIndex])~~ ~~if (pair.unused) {~~ ~~pair.unused = false;~~ ~~search(sequences, minHead, pair.word, currentPath,~~ ~~currentPathLen, longestPath);~~ ~~pair.unused = true;~~ } } This leads to tight enough code for the foreach loop in the search function: <syntaxhighlight lang="asm">LBB0_4: movl (%esi), %eax movb 19(%esp), %cl cmpb %cl, (%eax) jne LBB0_6 movl (%edi,%ebx,4), %ecx movl %eax, (%edi,%ebx,4) movl %ecx, (%esi) movl %edi, 8(%esp) movl 48(%esp), %eax movl %eax, 4(%esp) movl 12(%esp), %eax movl %eax, (%esp) movl 20(%esp), %eax calll __D25last_letter_first_letter26searchFNaAPyaxiKAPyaZv subl $12, %esp movl (%edi,%ebx,4), %eax movl (%esi), %ecx movl %ecx, (%edi,%ebx,4) movl %eax, (%esi) LBB0_6: addl $4, %esi decl %ebp jne LBB0_4</syntaxhighlight> The run-time is about 0.65 seconds with LDC2 compiler. The output is similar. ===Faster Version=== <syntaxhighlight lang="d">import std.stdio, std.algorithm, std.string, std.range, std.typecons; Tuple!(uint, string[]) findLongestChain(in string[] words) pure nothrow { static struct Pair { string word; bool unused; } uint nSolutions; void search(Pair[][] sequences, in size_t minHead, in string currWord, string[] currentPath, size_t currentPathLen, ref string[] longestPath) nothrow { currentPath[currentPathLen] = currWord; currentPathLen++; if (currentPathLen == longestPath.length) { nSolutions++; } else if (currentPathLen > longestPath.length) { nSolutions = 1; longestPath = currentPath[0 .. currentPathLen].dup; } // Recursive search. immutable size_t lastCharIndex = currWord[$ - 1] - minHead; if (lastCharIndex < sequences.length) foreach (ref pair; sequences[lastCharIndex]) if (pair.unused) { pair.unused = false; search(sequences, minHead, pair.word, currentPath, currentPathLen, longestPath); pair.unused = true; } } if (words.empty) typeof(return)(0, null); immutable heads = words.map!q{ a[0] }.array; immutable size_t minHead = reduce!min(heads[0], heads[1.. $].representation); immutable size_t maxHead = reduce!max(heads[0], heads[1.. $].representation); ~~string[] findLongestChain(string[] words) {~~ ~~auto heads = map!q{ a[0] }(words);~~ ~~size_t minHead = reduce!min(heads);~~ ~~size_t maxHead = reduce!max(heads);~~ auto sequences = new Pair[][](maxHead - minHead + 1, 0); foreach (const word; words) sequences[word[0] - minHead] ~= Pair(word, true); Line 472 ⟶ 1,517: string[] longestPath; // ~~try~~Try each item as possible start. foreach (seq; sequences) foreach (ref pair; seq) { Line 481 ⟶ 1,526: } return typeof(return)(nSolutions, longestPath); } Line 495 ⟶ 1,540: scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask".~~tolower()~~toLower.split(); // ~~remove~~Remove duplicates. pokemon.length -= ~~copy(uniq(~~pokemon.sort()), .uniq.copy(pokemon).length; ~~auto~~const sol = ~~findLongestChain(~~pokemon).findLongestChain; writeln("Maximum path length: ", sol[1].length); writeln("Paths of that length: ", ~~nSolutions~~sol[0]); writeln("Example path of that length:"); ~~foreach~~ writefln(~~i; iota~~"%(0, ~~cast~~ %-(~~int~~%s %)~~sol.length~~\n%)", sol[1].chunks(7)); }</syntaxhighlight> ~~writeln(" ", sol[i .. min(i+7, $)].join(" "));~~ {{out}} ~~}</lang>~~ <pre>Maximum path length: 23 ~~Runtime: about 0.20 seconds, dmd compiler.~~ Paths of that length: 1248 Example path of that length: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino</pre> Runtime: about 0.20 seconds with dmd compiler, about 0.15 seconds with ldc2 compiler. ===Alternative Version=== {{trans\|PicoLisp}} <syntaxhighlight lang="d">import std.stdio, std.algorithm, std.array, std.typecons, std.container, std.range; auto findChain(in string[] seq) pure nothrow /@safe/ { const adj = seq .map!(item => tuple(item, seq .filter!(x => x[0] == item[$ - 1]) .array)) .assocArray; SList!string res; foreach (immutable item; adj.byKey) { void inner(in string it, SList!string lst) nothrow { lst.insertFront(it); if (lst[].walkLength > res[].walkLength) res = lst; foreach (immutable x; adj[it]) if (!lst[].canFind(x)) inner(x, lst); } inner(item, SList!string()); } return res.array.retro; } void main() /@safe/ { "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask".split.findChain.writeln; }</syntaxhighlight> {{out}} <pre>["machamp", "petilil", "landorus", "scrafty", "yamask", "kricketune", "emboar", "registeel", "loudred", "darmanitan", "nosepass", "simisear", "relicanth", "heatmor", "rufflet", "trapinch", "haxorus", "seaking", "girafarig", "gabite", "exeggcute", "emolga", "audino"]</pre> Run-time is about 3.1 seconds with ldc2 compiler. =={{header\|Delphi}}== Visual implementation, this unit is a VCL Form with a Memo, a Button, a Checkbox, a DataGrid, a DBMemo, a DataSource and a ClientDataSet with tree fields (length integer,count integer,list memo): <~~lang~~syntaxhighlight lang="delphi">unit Unit1; interface Line 787 ⟶ 1,884: end; end.</~~lang~~syntaxhighlight> Runtime varies depending if you run the "optimized" version or not. Ranges from 6 to 18 seconds. NOTE: "optimized" version is actually a different algorithm, but in most cases returns the same results. =={{header\|EasyLang}}== <syntaxhighlight> repeat s$ = input until s$ = "" for n$ in strsplit s$ " " pok$[] &= n$ . . # chain$[] = [ ] proc search lng . . if lng > len chain$[] chain$[] = [ ] for j to lng chain$[] &= pok$[j] . . lastc$ = substr pok$[lng] len pok$[lng] 1 for i = lng + 1 to len pok$[] if substr pok$[i] 1 1 = lastc$ swap pok$[i] pok$[lng + 1] search lng + 1 swap pok$[i] pok$[lng + 1] . . . for i to len pok$[] swap pok$[i] pok$[1] search 1 swap pok$[i] pok$[1] . for p$ in chain$[] write p$ & " " . # input_data audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask </syntaxhighlight> {{out}} <pre> machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino </pre> =={{header\|Elixir}}== {{trans\|Ruby}} <syntaxhighlight lang="elixir">defmodule LastLetter_FirstLetter do def search(names) do first = Enum.group_by(names, &String.first/1) sequences = Enum.reduce(names, [], fn name,acc -> add_name(first, acc, [name]) end) max = Enum.max_by(sequences, &length/1) \|> length max_seqs = Enum.filter(sequences, fn seq -> length(seq) == max end) IO.puts "there are #{length(sequences)} possible sequences" IO.puts "the longest is #{max} names long" IO.puts "there are #{length(max_seqs)} such sequences. one is:" hd(max_seqs) \|> Enum.with_index \|> Enum.each(fn {name, idx} -> :io.fwrite " ~2w ~s~n", [idx+1, name] end) end defp add_name(first, sequences, seq) do last_letter = String.last(hd(seq)) potentials = Map.get(first, last_letter, []) -- seq if potentials == [] do [Enum.reverse(seq) \| sequences] else Enum.reduce(potentials, sequences, fn name, acc -> add_name(first, acc, [name \| seq]) end) end end end names = ~w( audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask ) LastLetter_FirstLetter.search(names)</syntaxhighlight> {{out}} <pre> there are 2076396 possible sequences the longest is 23 names long there are 1248 such sequences. one is: 1 machamp 2 petilil 3 landorus 4 scrafty 5 yamask 6 kricketune 7 emboar 8 registeel 9 loudred 10 darmanitan 11 nosepass 12 simisear 13 relicanth 14 heatmor 15 rufflet 16 trapinch 17 haxorus 18 seaking 19 girafarig 20 gabite 21 exeggcute 22 emolga 23 audino </pre> =={{header\|Erlang}}== This is a parallel version. It takes 2.1 seconds. The (commented out) serial version takes 7.1 seconds. Both times measured on my (low end) Mac Mini. I thought parallel code would help in getting the brownie points. But even a small increase to 100 Pokemons makes the code run for more than the few spare hours I have in the evening. <syntaxhighlight lang="erlang"> -module( last_letter_first_letter ). -export( [solve/1, task/0] ). solve( Names ) -> Dict = lists:foldl( fun dict_append/2, dict:new(), Names ), Chains = construct_chains_in_parallel( Dict ), % Chains = [construct_chain_from_key(Dict, X) \|\| X <- dict:fetch_keys(Dict)], lists:foldl( fun construct_chain_longest/2, [], Chains ). task() -> solve( binary:split(names(), <<" ">>, [global]) ). construct_chains_in_parallel( Dict ) -> My_pid = erlang:self(), Pids = [erlang:spawn( fun() -> My_pid ! {erlang:self(), construct_chain_from_key(Dict, X)} end) \|\| X <- dict:fetch_keys(Dict)], [receive {X, Chain} -> Chain end \|\| X <- Pids]. construct_chain_from_key( Dict, First_letter ) -> Names = construct_chain_names( dict:find(First_letter, Dict) ), construct_chain_from_names( Names, Dict, [] ). construct_chain_from_names( [], _Dict, Best_chain ) -> Best_chain; construct_chain_from_names( [{Name, Last_letter} \| T], Dict, Best_chain ) -> New_dict = dict_delete( Name, Dict ), New_chain = [Name \| construct_chain_from_key( New_dict, Last_letter )], construct_chain_from_names( T, Dict, construct_chain_longest(Best_chain, New_chain) ). construct_chain_longest( Chain1, Chain2 ) when length(Chain1) > length(Chain2) -> Chain1; construct_chain_longest( _Chain1, Chain2 ) -> Chain2. construct_chain_names( {ok, {Name, Last_letter}} ) -> [{Name, Last_letter}]; construct_chain_names( {ok, Values} ) -> Values; construct_chain_names( error ) -> []. dict_append( Name, Acc ) -> {First_letter, {Name, Last_letter}} = dict_item( Name ), dict:append( First_letter, {Name, Last_letter}, Acc ). dict_item( <<First_letter, _T/binary>>=Name ) -> Until_last_letter = erlang:byte_size( Name ) - 1, <<_H:Until_last_letter/binary, Last_letter>> = Name, {First_letter, {Name, Last_letter}}. dict_delete( <<First_letter, _T/binary>>=Name, Dict ) -> Name_last_letters = dict:fetch(First_letter, Dict), dict:store( First_letter, lists:keydelete(Name, 1, Name_last_letters), Dict ). names() -> <<"audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask">>. </syntaxhighlight> {{out}} <pre> 11> last_letter_first_letter:task(). [<<"machamp">>,<<"pinsir">>,<<"rufflet">>,<<"trapinch">>, <<"heatmor">>,<<"remoraid">>,<<"darmanitan">>, <<"nosepass">>,<<"starly">>,<<"yamask">>,<<"kricketune">>, <<"exeggcute">>,<<"emboar">>,<<"relicanth">>,<<"haxorus">>, <<"simisear">>,<<"registeel">>,<<"landorus">>,<<"seaking">>, <<"girafarig">>,<<"gabite">>,<<"emolga">>,<<"audino">>] </pre> =={{header\|Go}}== Depth first, starting with each possible name. <~~lang~~syntaxhighlight lang="go">package main import ( Line 849 ⟶ 2,133: } } }</~~lang~~syntaxhighlight> Output: <pre> Line 864 ⟶ 2,148: =={{header\|Haskell}}== Note: This takes ~80 seconds to complete on my machine. <~~lang~~syntaxhighlight ~~Haskell~~lang="haskell">import Data.List import qualified Data.ByteString.Char8 as B Line 886 ⟶ 2,170: isLink pl pr = B.last pl == B.head pr main = mapM_ B.putStrLn $ growChains $ map (\x -> [x]) allPokemon</~~lang~~syntaxhighlight> Output: <pre>machamp Line 911 ⟶ 2,195: emolga audino</pre> A simpler version (no ByteString), about 2.4 times slower (GHC -O3), same output: <syntaxhighlight lang="haskell">import Data.List allPokemon = words "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon \ \cresselia croagunk darmanitan deino emboar emolga exeggcute gabite \ \girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan \ \kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine \ \nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 \ \porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking \ \sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko \ \tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask" growChains :: [[String]] -> [String] growChains pcs \| nextChainSet == [] = head pcs \| otherwise = growChains nextChainSet where nextChainSet = pcs >>= findLinks findLinks pc = map (\x -> pc ++ [x]) $ filter (isLink $ last pc) (allPokemon \\ pc) isLink pl pr = last pl == head pr main = mapM_ putStrLn $ growChains $ map (\x -> [x]) allPokemon</syntaxhighlight> =={{header\|Icon}} and {{header\|Unicon}}== Works in both languages (brute force): <syntaxhighlight lang="unicon">global words procedure main() words := table() every word := genwords(&input) do { /words[word[1]] := [] put(words[word[1]], word) } bP := [] every p := getPath(!!words,[]) do if \p > bP then bP := copy(p) write("Longest: ",bP) every writes((!bP\|\|" ")\|"\n") end procedure getPath(word, p) if word == !p then return p if /words[word[-1]] then suspend p <- p \|\|\| [word] else suspend getPath(!words[word[-1]], p <- p \|\|\| [word]) end procedure genwords(f) while l := !f do l ? while tab(upto(&letters)) do suspend tab(many(&letters))\1 end</syntaxhighlight> Sample run on sample data: <pre> ->llfl <llfl.in Longest: 23 machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino -> </pre> =={{header\|J}}== Here, we use a brute force breadth-first search. Unless we know ahead of time how long "longest" is, we must try all possibilities to ensure that an unchecked possibility is not longer than a possibility which we have found. <~~lang~~syntaxhighlight lang="j">pokenames=: ;:0 :0-.LF audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite Line 935 ⟶ 2,278: end. r )</~~lang~~syntaxhighlight> The line <code>assert. 1e9>/8,$r</code> was added to avoid a very bad behavior from microsoft windows which appeared on different arguments, when intermediate results became too large (the machine would have to be rebooted when intermediate results became an order of magnitude larger than the available physical memory). By ensuring that the program would end before consuming that much virtual memory, this behavior from the operating system can be avoided. Note that [http://www.jsoftware.com/help/dictionary/dx009.htm 9!:21 and/or 9!:33] could also be used to prevent OS instability triggered by requesting too many resources. With this procedure we are able to conduct the entire search for this list of names: <~~lang~~syntaxhighlight lang="j">$R=: seqs pokenames 1248 23</~~lang~~syntaxhighlight> With this data set, we have 1248 sequences of names which have the longest possible length, and those sequences are 23 names long. Here's one of them: <~~lang~~syntaxhighlight lang="j"> >pokenames {~{.R machamp petilil Line 969 ⟶ 2,312: exeggcute emolga audino </~~lang~~syntaxhighlight> =={{header\|Java}}== <syntaxhighlight lang="java">// derived from C final class LastLetterFirstLetter { static int maxPathLength = 0; static int maxPathLengthCount = 0; static final StringBuffer maxPathExample = new StringBuffer(500); static final String[] names = {"audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"}; static void recursive(String[] part, int offset) { if (offset > maxPathLength) { maxPathLength = offset; maxPathLengthCount = 1; } else if (offset == maxPathLength) { maxPathLengthCount++; maxPathExample.setLength(0); for (int i = 0; i < offset; i++) { maxPathExample.append((i % 5 == 0 ? "\n " : " ")); maxPathExample.append(part[i]); } } final char lastChar = part[offset - 1].charAt(part[offset - 1].length()-1); for (int i = offset; i < part.length; i++) { if (part[i].charAt(0) == lastChar) { String tmp = names[offset]; names[offset] = names[i]; names[i] = tmp; recursive(names, offset+1); names[i] = names[offset]; names[offset] = tmp; } } } public static void main(String[] args) { for (int i = 0; i < names.length; i++) { String tmp = names[0]; names[0] = names[i]; names[i] = tmp; recursive(names, 1); names[i] = names[0]; names[0] = tmp; } System.out.println("maximum path length : " + maxPathLength); System.out.println("paths of that length : " + maxPathLengthCount); System.out.println("example path of that length:" + maxPathExample); } } </syntaxhighlight> Output:<pre>maximum path length : 23 paths of that length : 1248 example path of that length: machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> =={{header\|JavaScript}}== {{Works with\|Node.js}} (Required for the ''process'' object) <syntaxhighlight lang="javascript">/* * Find the letter the word ends on * @param {string} word * @returns {string} / const endsWith = word => word[word.length - 1]; /* * Remove the used elements from the candidate elements * @param {Array<string>} words Candidate words * @param {Array<string>} used Used words * @returns {} / const getCandidates = (words, used) => words.filter(e => !used.includes(e)); /** * Build a map of letters to words that start with that letter * @param {Array<string>} words * @returns {Map<string, Array<string>>} / const buildLookup = words => { const lookup = new Map(); words.forEach(e => { const start = e[0]; lookup.set(start, [...(lookup.get(start) \|\| []), e]); }); return lookup; }; /* * Main function * @param {Array<string>} names / const findPaths = names => { const t0 = process.hrtime(); console.log('Checking:', names.length, 'names'); const lookup = buildLookup(names); let maxNum = 0; let maxPaths = []; const parseResult = arr => { if (typeof arr[0] === 'object') { arr.forEach(el => parseResult(el)) } else { if (arr.length > maxNum) { maxNum = arr.length; maxPaths = [arr]; } if (arr.length === maxNum) { maxPaths.push(arr) } } }; const searchWords = (word, res) => { const cs = getCandidates(lookup.get(endsWith(word)) \|\| [], res); return cs.length ? cs.map(e => searchWords(e, [...res, e])) : res; }; names.forEach(word => { const res = searchWords(word, [word]); parseResult(res); }); const t1 = process.hrtime(t0); console.info('Execution time (hr): %ds %dms', t1[0], t1[1] / 1000000); console.log('Max Path:', maxNum); console.log('Matching Paths:', maxPaths.length); console.log('Example Path:', maxPaths[0]); }; const pokimon = ["audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"]; findPaths(pokimon); </syntaxhighlight> <pre> Checking: 70 names Execution time (hr): 2s 121.778223ms Max Path: 23 Matching Paths: 1249 Example Path: [ 'machamp', 'petilil', 'landorus', 'scrafty', 'yamask', 'kricketune', 'emboar', 'registeel', 'loudred', 'darmanitan', 'nosepass', 'simisear', 'relicanth', 'heatmor', 'rufflet', 'trapinch', 'haxorus', 'seaking', 'girafarig', 'gabite', 'exeggcute', 'emolga', 'audino' ] </pre> =={{header\|jq}}== Short and sweet, with a nod to efficiency in the form of a dictionary for lookup of still-available words. jq's "debug" filter is used to illustrate how progress can be monitored. It writes to stderr. If your jq does not include "debug", simply remove or comment-out the entire line. '''Utility functions''': <syntaxhighlight lang="jq"># convert a list of unique words to a dictionary def dictionary: reduce .[] as $word ({}; .[$word[0:1]] += [$word]) ; # remove "word" from the input dictionary assuming the key is already there: def remove(word): .[word[0:1]] -= [word];</syntaxhighlight> '''The last-letter/first-letter game''': <syntaxhighlight lang="ja"># left-right admissibility def admissible: .[0][-1:] == .[1][0:1]; # input: [word, dictionary_of_available_words_excluding_word] # output: a (possibly empty) stream of admissible values: [next_word, updated_dictionary], # where next_word can follow the given word. def next: .[0] as $word \| if $word == null then empty else .[1] as $dictionary \| $word[-1:] as $last \| (($dictionary[$last] // []) \| .[]) as $next \| [ $next, ($dictionary \| remove($next)) ] end ; # Produce an array representing a thread starting at "word": # Input: [word, dictionary_of_available_words] def thread: if .[1] == [] then [ .[0] ] else (next // null) as $next \| [.[0]] + (if $next then ($next \| thread) else [] end) end ; # Input: list of words # Output: [ maximal_length, maximal_thread] def maximal: def maximum(start): . as $dictionary \| reduce ( [start, ($dictionary \| remove(start))] \| thread ) as $thread ([0, null]; ($thread\|length) as $l \| if $l > .[0] then [$l, $thread] else . end ); dictionary as $dictionary \| reduce .[] as $name ( [0,null]; ($dictionary \| maximum($name)) as $ans # If your jq does not include "debug", simply remove or comment-out the following line: \| ([$name, $ans[0]] \| debug) as $debug \| if $ans[0] > .[0] then $ans else . end );</syntaxhighlight> '''Example''': <syntaxhighlight lang="jq">def names: ["audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask" ] ; names \| maximal</syntaxhighlight> {{out}} (scrollable) The "DEBUG" lines are included to illustrate how progress can be monitored. They show the maximal length for the indicated initial word. <div style="overflow:scroll; height:400px;"> <syntaxhighlight lang="sh">$ jq -n -f Last_letter-first_letter.jq ["DEBUG:",["audino",1]] ["DEBUG:",["bagon",20]] ["DEBUG:",["baltoy",21]] ["DEBUG:",["banette",20]] ["DEBUG:",["bidoof",1]] ["DEBUG:",["braviary",21]] ["DEBUG:",["bronzor",22]] ["DEBUG:",["carracosta",2]] ["DEBUG:",["charmeleon",20]] ["DEBUG:",["cresselia",2]] ["DEBUG:",["croagunk",21]] ["DEBUG:",["darmanitan",20]] ["DEBUG:",["deino",1]] ["DEBUG:",["emboar",19]] ["DEBUG:",["emolga",2]] ["DEBUG:",["exeggcute",19]] ["DEBUG:",["gabite",20]] ["DEBUG:",["girafarig",20]] ["DEBUG:",["gulpin",20]] ["DEBUG:",["haxorus",20]] ["DEBUG:",["heatmor",20]] ["DEBUG:",["heatran",20]] ["DEBUG:",["ivysaur",22]] ["DEBUG:",["jellicent",21]] ["DEBUG:",["jumpluff",1]] ["DEBUG:",["kangaskhan",20]] ["DEBUG:",["kricketune",20]] ["DEBUG:",["landorus",21]] ["DEBUG:",["ledyba",2]] ["DEBUG:",["loudred",21]] ["DEBUG:",["lumineon",20]] ["DEBUG:",["lunatone",20]] ["DEBUG:",["machamp",23]] ["DEBUG:",["magnezone",20]] ["DEBUG:",["mamoswine",20]] ["DEBUG:",["nosepass",19]] ["DEBUG:",["petilil",22]] ["DEBUG:",["pidgeotto",1]] ["DEBUG:",["pikachu",1]] ["DEBUG:",["pinsir",22]] ["DEBUG:",["poliwrath",21]] ["DEBUG:",["poochyena",2]] ["DEBUG:",["porygon2",1]] ["DEBUG:",["porygonz",1]] ["DEBUG:",["registeel",21]] ["DEBUG:",["relicanth",21]] ["DEBUG:",["remoraid",21]] ["DEBUG:",["rufflet",21]] ["DEBUG:",["sableye",20]] ["DEBUG:",["scolipede",20]] ["DEBUG:",["scrafty",21]] ["DEBUG:",["seaking",21]] ["DEBUG:",["sealeo",1]] ["DEBUG:",["silcoon",20]] ["DEBUG:",["simisear",21]] ["DEBUG:",["snivy",21]] ["DEBUG:",["snorlax",1]] ["DEBUG:",["spoink",21]] ["DEBUG:",["starly",21]] ["DEBUG:",["tirtouga",2]] ["DEBUG:",["trapinch",20]] ["DEBUG:",["treecko",1]] ["DEBUG:",["tyrogue",20]] ["DEBUG:",["vigoroth",21]] ["DEBUG:",["vulpix",1]] ["DEBUG:",["wailord",21]] ["DEBUG:",["wartortle",20]] ["DEBUG:",["whismur",22]] ["DEBUG:",["wingull",22]] ["DEBUG:",["yamask",20]] [ 23, [ "machamp", "petilil", "landorus", "scrafty", "yamask", "kricketune", "emboar", "registeel", "loudred", "darmanitan", "nosepass", "simisear", "relicanth", "heatmor", "rufflet", "trapinch", "haxorus", "seaking", "girafarig", "gabite", "exeggcute", "emolga", "audino" ] ]</syntaxhighlight></div> =={{header\|Julia}}== {{works with\|Julia\|0.6}} {{trans\|Python}} <syntaxhighlight lang="julia">using IterTools.groupby orderwords(words::Vector) = Dict(w[1][1] => Set(w) for w in groupby(first, words)) longest(a, b) = ifelse(length(a) > length(b), a, b) function linkfirst(byfirst::Dict, sofar::Vector) @assert(!isempty(sofar)) chmatch = sofar[end][end] if ! haskey(byfirst, chmatch) return sofar end options = setdiff(byfirst[chmatch], sofar) if isempty(options) return sofar else alternatives = ( linkfirst(byfirst, vcat(sofar, word)) for word in options ) mx = reduce(longest, alternatives) return mx end end function llfl(words) byfirst = orderwords(words) alternatives = ( linkfirst(byfirst, [word]) for word in words ) return reduce(longest, alternatives) end pokemon = String.(unique(split(""" audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask """))) l = llfl(pokemon) println("Example of longest seq.:\n", join(l, ", ")) println("Max length: ", length(l)</syntaxhighlight> {{out}} <pre>Example of longest seq.: machamp, pinsir, relicanth, heatmor, registeel, landorus, starly, yamask, kricketune, emboar, rufflet, trapinch, haxorus, simisear, remoraid, darmanitan, nosepass, seaking, girafarig, gabite, exeggcute, emolga, audino Max length: 23</pre> =={{header\|Kotlin}}== {{trans\|Java}} <syntaxhighlight lang="scala">// version 1.1.2 var maxPathLength = 0 var maxPathLengthCount = 0 val maxPathExample = StringBuilder(500) val names = arrayOf( "audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask" ) fun search(part: Array<String>, offset: Int) { if (offset > maxPathLength) { maxPathLength = offset maxPathLengthCount = 1 } else if (offset == maxPathLength) { maxPathLengthCount++ maxPathExample.setLength(0) for (i in 0 until offset) { maxPathExample.append(if (i % 5 == 0) "\n " else " ") maxPathExample.append(part[i]) } } val lastChar = part[offset - 1].last() for (i in offset until part.size) { if (part[i][0] == lastChar) { val tmp = names[offset] names[offset] = names[i] names[i] = tmp search(names, offset + 1) names[i] = names[offset] names[offset] = tmp } } } fun main(args: Array<String>) { for (i in 0 until names.size) { val tmp = names[0] names[0] = names[i] names[i] = tmp search(names, 1) names[i] = names[0] names[0] = tmp } println("Maximum path length : $maxPathLength") println("Paths of that length : $maxPathLengthCount") println("Example path of that length : $maxPathExample") }</syntaxhighlight> {{out}} <pre> Maximum path length : 23 Paths of that length : 1248 Example path of that length : machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> =={{header\|Lua}}== In lieu of the poorly-specified extra-credit portion (e.g. are the two Nidoran's to be considered same or unique?), I chose to expand on the output portion of the core task. <syntaxhighlight lang="lua">-- BUILDING: pokemon = [[ audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask]] words, inits, succs = {}, {}, {} for word in pokemon:gmatch("%S+") do table.insert(words, word) local ch = word:sub(1,1) inits[ch] = inits[ch] or {} table.insert(inits[ch], word) end for _,word in pairs(words) do succs[word] = {} local ch = word:sub(-1,-1) if inits[ch] then for _,succ in pairs(inits[ch]) do if succ~=word then table.insert(succs[word],succ) end end end end -- SEARCHING: function expand(list, used, answer) local word = list[#list] for _,succ in ipairs(succs[word]) do if not used[succ] then used[succ] = true list[#list+1] = succ if #list == answer.len then local perm = table.concat(list," ") answer.perms[perm] = perm answer.num = answer.num + 1 elseif #list > answer.len then answer.len = #list local perm = table.concat(list," ") answer.perms = {[perm] = perm} answer.num = 1 end expand(list, used, answer) list[#list] = nil used[succ] = nil end end end answers = {} for _,word in ipairs(words) do local answer = { word=word, len=0, num=0, perms={} } answers[#answers+1] = answer expand({word}, {[word]=true}, answer) end -- REPORTING: table.sort(answers, function(a,b) return a.len<b.len or (a.len==b.len and a.word<b.word) end) print("first word length count example") print("---------- ------ ----- -------...") for _,answer in pairs(answers) do local perm = next(answer.perms) or "" print(string.format("%10s %6d %5d %s", answer.word, answer.len, answer.num, perm)) end</syntaxhighlight> {{out}} <pre>first word length count example ---------- ------ ----- -------... audino 0 0 bidoof 0 0 deino 0 0 jumpluff 0 0 pidgeotto 0 0 pikachu 0 0 porygon2 0 0 porygonz 0 0 sealeo 0 0 snorlax 0 0 treecko 0 0 vulpix 0 0 carracosta 2 1 carracosta audino cresselia 2 1 cresselia audino emolga 2 1 emolga audino ledyba 2 1 ledyba audino poochyena 2 1 poochyena audino tirtouga 2 1 tirtouga audino emboar 19 96 emboar relicanth heatmor rufflet trapinch haxorus simisear registeel landorus seaking girafarig gulpin nosepass scrafty yamask kricketune exeggcute emolga audino exeggcute 19 96 exeggcute emboar relicanth haxorus seaking girafarig gulpin nosepass simisear rufflet trapinch heatmor registeel landorus snivy yamask kricketune emolga audino nosepass 19 192 nosepass snivy yamask kricketune exeggcute emboar rufflet trapinch heatmor registeel landorus simisear relicanth haxorus seaking girafarig gabite emolga audino bagon 20 192 bagon nosepass simisear relicanth heatmor rufflet trapinch haxorus scrafty yamask kricketune emboar registeel landorus seaking girafarig gabite exeggcute emolga audino banette 20 192 banette exeggcute emboar relicanth heatmor registeel landorus starly yamask kangaskhan nosepass simisear rufflet trapinch haxorus seaking girafarig gabite emolga audino charmeleon 20 192 charmeleon nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite emboar registeel landorus starly yamask kricketune exeggcute emolga audino darmanitan 20 192 darmanitan nosepass seaking girafarig gabite exeggcute emboar relicanth haxorus simisear rufflet trapinch heatmor registeel landorus starly yamask kricketune emolga audino gabite 20 96 gabite emboar rufflet trapinch heatmor relicanth haxorus simisear registeel landorus seaking girafarig gulpin nosepass snivy yamask kricketune exeggcute emolga audino girafarig 20 480 girafarig gabite emboar registeel landorus spoink kangaskhan nosepass simisear rufflet trapinch heatmor relicanth haxorus snivy yamask kricketune exeggcute emolga audino gulpin 20 192 gulpin nosepass simisear rufflet trapinch heatmor relicanth haxorus snivy yamask kricketune emboar registeel landorus seaking girafarig gabite exeggcute emolga audino haxorus 20 288 haxorus starly yamask kricketune exeggcute emboar registeel landorus simisear rufflet trapinch heatmor remoraid darmanitan nosepass seaking girafarig gabite emolga audino heatmor 20 432 heatmor rufflet trapinch heatran nosepass simisear relicanth haxorus seaking girafarig gabite emboar registeel landorus starly yamask kricketune exeggcute emolga audino heatran 20 192 heatran nosepass simisear relicanth haxorus seaking girafarig gabite exeggcute emboar rufflet trapinch heatmor registeel landorus starly yamask kricketune emolga audino kangaskhan 20 192 kangaskhan nosepass seaking girafarig gabite exeggcute emboar relicanth haxorus simisear rufflet trapinch heatmor registeel landorus starly yamask kricketune emolga audino kricketune 20 96 kricketune exeggcute emboar relicanth heatmor rufflet trapinch haxorus simisear registeel landorus scrafty yamask kangaskhan nosepass seaking girafarig gabite emolga audino lumineon 20 192 lumineon nosepass seaking girafarig gabite exeggcute emboar rufflet trapinch heatmor relicanth haxorus simisear registeel landorus starly yamask kricketune emolga audino lunatone 20 192 lunatone emboar rufflet trapinch heatmor registeel landorus starly yamask kangaskhan nosepass simisear relicanth haxorus seaking girafarig gabite exeggcute emolga audino magnezone 20 192 magnezone exeggcute emboar registeel landorus snivy yamask kangaskhan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite emolga audino mamoswine 20 192 mamoswine exeggcute emboar relicanth haxorus seaking girafarig gulpin nosepass simisear rufflet trapinch heatmor registeel landorus snivy yamask kricketune emolga audino sableye 20 192 sableye emboar relicanth heatmor registeel landorus simisear rufflet trapinch haxorus seaking girafarig gulpin nosepass starly yamask kricketune exeggcute emolga audino scolipede 20 192 scolipede exeggcute emboar relicanth haxorus seaking girafarig gulpin nosepass simisear rufflet trapinch heatmor registeel landorus snivy yamask kricketune emolga audino silcoon 20 192 silcoon nosepass simisear rufflet trapinch haxorus scrafty yamask kricketune exeggcute emboar relicanth heatmor registeel landorus seaking girafarig gabite emolga audino trapinch 20 576 trapinch heatmor registeel landorus simisear remoraid darmanitan nosepass scrafty yamask kricketune exeggcute emboar relicanth haxorus seaking girafarig gabite emolga audino tyrogue 20 192 tyrogue emboar rufflet trapinch heatmor registeel landorus seaking girafarig gulpin nosepass simisear relicanth haxorus snivy yamask kricketune exeggcute emolga audino wartortle 20 192 wartortle exeggcute emboar registeel landorus snivy yamask kangaskhan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite emolga audino yamask 20 96 yamask kangaskhan nosepass seaking girafarig gabite emboar rufflet trapinch heatmor registeel landorus simisear relicanth haxorus spoink kricketune exeggcute emolga audino baltoy 21 96 baltoy yamask kangaskhan nosepass simisear rufflet trapinch heatmor relicanth haxorus seaking girafarig gabite exeggcute emboar registeel landorus spoink kricketune emolga audino braviary 21 96 braviary yamask kangaskhan nosepass seaking girafarig gabite exeggcute emboar relicanth haxorus simisear rufflet trapinch heatmor registeel landorus spoink kricketune emolga audino croagunk 21 288 croagunk kangaskhan nosepass seaking girafarig gabite emboar rufflet trapinch heatmor registeel landorus simisear relicanth haxorus starly yamask kricketune exeggcute emolga audino jellicent 21 768 jellicent trapinch haxorus seaking girafarig gabite exeggcute emboar relicanth heatmor remoraid darmanitan nosepass simisear registeel landorus snivy yamask kricketune emolga audino landorus 21 192 landorus seaking girafarig gabite emboar relicanth heatmor rufflet trapinch haxorus simisear registeel loudred darmanitan nosepass starly yamask kricketune exeggcute emolga audino loudred 21 192 loudred darmanitan nosepass seaking girafarig gabite exeggcute emboar rufflet trapinch haxorus simisear relicanth heatmor registeel landorus snivy yamask kricketune emolga audino poliwrath 21 912 poliwrath heatmor remoraid darmanitan nosepass simisear registeel landorus seaking girafarig gabite exeggcute emboar rufflet trapinch haxorus scrafty yamask kricketune emolga audino registeel 21 192 registeel landorus simisear rufflet trapinch heatmor remoraid darmanitan nosepass seaking girafarig gabite exeggcute emboar relicanth haxorus starly yamask kricketune emolga audino relicanth 21 240 relicanth heatmor rufflet trapinch haxorus simisear registeel landorus seaking girafarig gabite exeggcute emboar remoraid darmanitan nosepass starly yamask kricketune emolga audino remoraid 21 192 remoraid darmanitan nosepass simisear relicanth heatmor registeel landorus scrafty yamask kricketune exeggcute emboar rufflet trapinch haxorus seaking girafarig gabite emolga audino rufflet 21 240 rufflet trapinch heatmor remoraid darmanitan nosepass seaking girafarig gabite emboar registeel landorus simisear relicanth haxorus starly yamask kricketune exeggcute emolga audino scrafty 21 96 scrafty yamask kricketune exeggcute emboar rufflet trapinch heatmor relicanth haxorus spoink kangaskhan nosepass simisear registeel landorus seaking girafarig gabite emolga audino seaking 21 192 seaking girafarig gabite emboar rufflet trapinch heatmor relicanth haxorus simisear registeel landorus snivy yamask kangaskhan nosepass spoink kricketune exeggcute emolga audino simisear 21 384 simisear rufflet trapinch haxorus spoink kricketune exeggcute emboar relicanth heatmor registeel landorus snivy yamask kangaskhan nosepass seaking girafarig gabite emolga audino snivy 21 96 snivy yamask kricketune exeggcute emboar registeel landorus simisear rufflet trapinch heatmor relicanth haxorus spoink kangaskhan nosepass seaking girafarig gabite emolga audino spoink 21 288 spoink kangaskhan nosepass snivy yamask kricketune emboar relicanth heatmor rufflet trapinch haxorus simisear registeel landorus seaking girafarig gabite exeggcute emolga audino starly 21 96 starly yamask kangaskhan nosepass simisear rufflet trapinch heatmor relicanth haxorus seaking girafarig gabite exeggcute emboar registeel landorus spoink kricketune emolga audino vigoroth 21 912 vigoroth haxorus simisear registeel landorus starly yamask kricketune exeggcute emboar rufflet trapinch heatmor remoraid darmanitan nosepass seaking girafarig gabite emolga audino wailord 21 192 wailord darmanitan nosepass seaking girafarig gabite exeggcute emboar rufflet trapinch haxorus simisear relicanth heatmor registeel landorus snivy yamask kricketune emolga audino bronzor 22 864 bronzor registeel landorus seaking girafarig gabite emboar rufflet trapinch heatmor remoraid darmanitan nosepass simisear relicanth haxorus snivy yamask kricketune exeggcute emolga audino ivysaur 22 864 ivysaur registeel landorus seaking girafarig gabite emboar rufflet trapinch heatmor remoraid darmanitan nosepass simisear relicanth haxorus snivy yamask kricketune exeggcute emolga audino petilil 22 384 petilil landorus simisear rufflet trapinch heatmor relicanth haxorus starly yamask kricketune exeggcute emboar registeel loudred darmanitan nosepass seaking girafarig gabite emolga audino pinsir 22 864 pinsir rufflet trapinch heatmor registeel landorus seaking girafarig gabite exeggcute emboar relicanth haxorus simisear remoraid darmanitan nosepass snivy yamask kricketune emolga audino whismur 22 864 whismur registeel landorus seaking girafarig gabite emboar rufflet trapinch heatmor remoraid darmanitan nosepass simisear relicanth haxorus snivy yamask kricketune exeggcute emolga audino wingull 22 384 wingull landorus snivy yamask kricketune emboar rufflet trapinch haxorus simisear relicanth heatmor registeel loudred darmanitan nosepass seaking girafarig gabite exeggcute emolga audino machamp 23 1248 machamp petilil landorus simisear relicanth haxorus starly yamask kricketune exeggcute emboar rufflet trapinch heatmor registeel loudred darmanitan nosepass seaking girafarig gabite emolga audino</pre> =={{header\|Mathematica}}/{{header\|Wolfram Language}}== <syntaxhighlight lang="mathematica">longestChain[list_] := NestWhileList[ Append @@@ Select[DeleteDuplicatesBy[ Tuples[{#, list}], {#[[1, 1]], #[[2]]} &], ! MemberQ @@ # && StringTake[#[[1, -1]], -1] == StringTake[#[[2]], 1] &] &, List /@ list, # != {} &][[-2, 1]]; Print[longestChain[{"audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"}]];</syntaxhighlight> Uses the tactic of only checking chains with the same starting and ending values. {{out}} <pre>{baltoy, yamask, kangaskhan, nosepass, sableye, emboar, registeel, landorus, scolipede, emolga, audino}</pre> =={{header\|Nim}}== Using bit sets of indexes. The program runs in 0.5s. <syntaxhighlight lang="nim">import tables const Names = ["audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"] type Index = range[0..Names.len-1] IndexSet = set[Index] Successors = Table[Index, IndexSet] const All = {Index.low..Index.high} # All indexes. func initSuccessors(): Successors {.compileTime.} = ## Build the mapping from name indexes to set of possible successor indexes. var names: Table[char, IndexSet] # Map first char to IndexSet. for idx, name in Names: names.mgetOrPut(name[0], {}).incl(idx) for idx, name in Names: result[idx] = names.getOrDefault(name[^1]) - {idx} # Mapping name index -> set of successor indexes. const Succ = initSuccessors() proc search(starts, available: IndexSet): seq[Index] = ## Search one of the longest sequence of indexes for given ## starting indexes and given available name indexes. var maxLen = -1 for idx in starts available: let list = search(Succ[idx], available - {idx}) if list.len > maxLen: result = idx & list maxLen = list.len let list = search(starts = All, available = All) echo "Longest lists have length: ", list.len echo "One of these lists is:" for idx in list: echo Names[idx]</syntaxhighlight> {{out}} <pre>Longest lists have length: 23 One of these lists is: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino</pre> =={{header\|ooRexx}}== <syntaxhighlight lang="oorexx"> -- create the searcher and run it searcher = .chainsearcher~new ::class chainsearcher ::method init expose max searchsize currentlongest pokemon_names = "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon" - "cresselia croagunk darmanitan deino emboar emolga exeggcute gabite" - "girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan" - "kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine" - "nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2" - "porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking" - "sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko" - "tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask" pokemon = pokemon_names~makearray(" ") searchsize = pokemon~items currentlongest = 0 say "searching" searchsize "names..." longestchain = .array~new -- run the sequence using each possible starting pokemon loop i = 1 to pokemon~items -- swap the ith name to the front of our list self~swap(pokemon, 1, i) -- run the chain from here self~searchChain(pokemon, longestchain, 2) -- swap the name back so we have the list in original form self~swap(pokemon, 1, i) end say "maximum path length:" longestchain~items say "paths of that length:" max say "example path of that length:" loop name over longestchain say " "name end ::method swap use arg list, a, b tmp = list[a] list[a] = list[b] list[b] = tmp -- recursive search routine for adding to the chain ::method searchChain expose max searchsize currentlongest use arg pokemon, longestchain, currentchain -- get the last character lastchar = pokemon[currentchain - 1]~right(1) -- now we search through all of the permutations of remaining -- matches to see if we can find a longer chain loop i = currentchain to searchsize -- for every candidate name from here, recursively extend the chain. if pokemon[i]~left(1) == lastchar then do if currentchain == currentLongest then max += 1 -- have we now gone deeper than the current longest chain? else if currentchain > currentLongest then do -- chuck this result and refill with current set longestchain~empty longestchain~appendall(pokemon~section(1, currentchain - 1)) longestchain~append(pokemon[i]) max = 1 currentLongest = currentchain end -- perform the swap again self~swap(pokemon, currentchain, i) -- run the chain from here self~searchChain(pokemon, longestchain, currentchain + 1) -- swap the name back so we have the list in original form self~swap(pokemon, currentchain, i) end end </syntaxhighlight> <pre> searching 70 names... maximum path length: 23 paths of that length: 1248 example path of that length: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino </pre> =={{header\|OpenEdge/Progress}}== The following gets the job done, but the time taken (40 minutes) is somewhat worrying when compared to other language solutions. So I am not going after the brownie points just yet... <~~lang~~syntaxhighlight lang="progress">DEFINE VARIABLE cpokemon AS CHARACTER INITIAL "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon ~ cresselia croagunk darmanitan deino emboar emolga exeggcute gabite ~ girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan ~ Line 1,057 ⟶ 3,256: IF lcontinue = FALSE THEN STOP. END.</~~lang~~syntaxhighlight> Output: Line 1,073 ⟶ 3,272: Yes No ---------------------------</pre> =={{header\|Perl}}== This is rather 'one liner' code, not to be used in production. The idea is to try all possible variants recursively. First, it creates the map-like structure: first letter → array of (name + last letter). During the cycle it uses @w as stack; @m keeps the longest sequence which is copied from @w; to prevent the words from appearing twice, they are (temporarily) deleted from the structure keeping the value in a stack variable. <syntaxhighlight lang="perl">use strict; my(%f,@m); /^(.).(.)$/,$f{$1}{$_}=$2 for qw( audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask ); sub poke { our @w; my $h = $f{$_[0]}; for my $word (keys %$h) { my $v = $h->{$word}; delete $h->{$word}; push @w, $word; @m = @w if @w > @m; poke($v); pop @w; $h->{$word} = $v; } } poke($_) for keys %f; print @m.": @m\n";</syntaxhighlight> {{out}} <pre>23: machamp petilil landorus seaking girafarig gabite emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus scrafty yamask kricketune exeggcute emolga audino</pre> =={{header\|Phix}}== Using simple start-with-same-letter word chains to minimise the number of elements we have to consider: <!--<syntaxhighlight lang="phix">(phixonline)--> <span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span> <span style="color: #008080;">constant</span> <span style="color: #000000;">words</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #008000;">"audino"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"bagon"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"baltoy"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"banette"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"bidoof"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"braviary"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"bronzor"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"carracosta"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"charmeleon"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"cresselia"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"croagunk"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"darmanitan"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"deino"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"emboar"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"emolga"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"exeggcute"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"gabite"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"girafarig"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"gulpin"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"haxorus"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"heatmor"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"heatran"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"ivysaur"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"jellicent"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"jumpluff"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"kangaskhan"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"kricketune"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"landorus"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"ledyba"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"loudred"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"lumineon"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"lunatone"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"machamp"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"magnezone"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"mamoswine"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"nosepass"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"petilil"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"pidgeotto"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"pikachu"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"pinsir"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"poliwrath"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"poochyena"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"porygon2"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"porygonz"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"registeel"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"relicanth"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"remoraid"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"rufflet"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"sableye"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"scolipede"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"scrafty"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"seaking"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"sealeo"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"silcoon"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"simisear"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"snivy"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"snorlax"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"spoink"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"starly"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"tirtouga"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"trapinch"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"treecko"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"tyrogue"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"vigoroth"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"vulpix"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"wailord"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"wartortle"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"whismur"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"wingull"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"yamask"</span><span style="color: #0000FF;">}</span> <span style="color: #008080;">function</span> <span style="color: #000000;">word_chains</span><span style="color: #0000FF;">()</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">first</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">256</span><span style="color: #0000FF;">),</span> <span style="color: #000080;font-style:italic;">-- start of chains for a given letter -- first['a']=1, first['b']=2, first['c']=8, etc.</span> <span style="color: #000000;">snext</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">))</span> <span style="color: #000080;font-style:italic;">-- chains of words starting with the same letter -- a: snext[1]=0, b: snext[2..7]={3,4,5,6,7,0}, etc.</span> <span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">words</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">][</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">if</span> <span style="color: #000000;">first</span><span style="color: #0000FF;">[</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">]=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">first</span><span style="color: #0000FF;">[</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">i</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #008080;">if</span> <span style="color: #000000;">words</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">][</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]=</span><span style="color: #000000;">ch</span> <span style="color: #008080;">then</span> <span style="color: #000000;">snext</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">j</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #008080;">end</span> <span style="color: #008080;">for</span> <span style="color: #008080;">end</span> <span style="color: #008080;">for</span> <span style="color: #008080;">return</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">first</span><span style="color: #0000FF;">,</span><span style="color: #000000;">snext</span><span style="color: #0000FF;">}</span> <span style="color: #008080;">end</span> <span style="color: #008080;">function</span> <span style="color: #008080;">constant</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">first</span><span style="color: #0000FF;">,</span><span style="color: #000000;">snext</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">word_chains</span><span style="color: #0000FF;">()</span> <span style="color: #000080;font-style:italic;">-- maintain words already taken as a linked list:</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">tstart</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">taken</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">))</span> <span style="color: #000080;font-style:italic;">-- 0=no, -1=end of chain, +ve=next -- and keep a copy of the best for later</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">bstart</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">best</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">maxn</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">count</span> <span style="color: #008080;">procedure</span> <span style="color: #000000;">find_path</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">last</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">next</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">first</span><span style="color: #0000FF;">[</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">while</span> <span style="color: #000000;">next</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">do</span> <span style="color: #008080;">if</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">next</span><span style="color: #0000FF;">]=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">last</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">next</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">next</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #000000;">find_path</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">[</span><span style="color: #000000;">next</span><span style="color: #0000FF;">][$],</span><span style="color: #000000;">next</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">last</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">next</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #000000;">next</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">snext</span><span style="color: #0000FF;">[</span><span style="color: #000000;">next</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">end</span> <span style="color: #008080;">while</span> <span style="color: #008080;">if</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">></span><span style="color: #000000;">maxn</span> <span style="color: #008080;">then</span> <span style="color: #000000;">bstart</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">tstart</span> <span style="color: #000000;">best</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">deep_copy</span><span style="color: #0000FF;">(</span><span style="color: #000000;">taken</span><span style="color: #0000FF;">)</span> <span style="color: #000000;">maxn</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">n</span> <span style="color: #000000;">count</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span> <span style="color: #008080;">elsif</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">=</span><span style="color: #000000;">maxn</span> <span style="color: #008080;">then</span> <span style="color: #000000;">count</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span> <span style="color: #004080;">atom</span> <span style="color: #000000;">t0</span><span style="color: #0000FF;">=</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #000000;">tstart</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">i</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #000000;">find_path</span><span style="color: #0000FF;">(</span><span style="color: #000000;">words</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">][$],</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span> <span style="color: #000000;">taken</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span> <span style="color: #008080;">end</span> <span style="color: #008080;">for</span> <span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"Runtime: %2.3f seconds. Max length:%d, found %d of such, one of which is:\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()-</span><span style="color: #000000;">t0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">maxn</span><span style="color: #0000FF;">,</span><span style="color: #000000;">count</span><span style="color: #0000FF;">})</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span> <span style="color: #008080;">while</span> <span style="color: #000000;">bstart</span><span style="color: #0000FF;">!=-</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #000000;">words</span><span style="color: #0000FF;">[</span><span style="color: #000000;">bstart</span><span style="color: #0000FF;">])</span> <span style="color: #000000;">bstart</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">best</span><span style="color: #0000FF;">[</span><span style="color: #000000;">bstart</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">end</span> <span style="color: #008080;">while</span> <span style="color: #7060A8;">assert</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">maxn</span><span style="color: #0000FF;">)</span> <span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%s\n"</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">join_by</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" "</span><span style="color: #0000FF;">))</span> <!--</syntaxhighlight>--> {{out}} <pre> Runtime: 0.625 seconds. Max length:23, found 1248 of such, one of which is: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino </pre> My claim for the extra brownie points, using the list from the Racket entry: <pre> Runtime: 0.000 seconds. Max length:2, found 9 of such, one of which is: Porygon-Z Zubat </pre> Which is quite correct: 9 names begin with 'Z', and plenty with 'T' but none with 't' ;-)<br> Adding a couple of upper(), it found a 302 in a couple of minutes but was still on permutations starting with word[1] when I got bored and killed it, quickly calculating at the very least another 4.5 days and quite probably not finishing within my lifetime... =={{header\|Picat}}== It's a little faster with the words sorted on decreasing lengths (<code>words2</code>): 9.43s vs 11.742s. <syntaxhighlight lang="picat">go => words(Words), % Words that starts with same letter as <this words>'s last letter. Starts = new_map(), foreach(Word in Words) S = [ Word2 : Word2 in Words, Word != Word2, Word.last() = Word2.first()], Starts.put(Word,S) end, % Sort the words according to lengths in decreasing order. Words2 = [W : W=_ in Starts.map_to_list().qsort(sort_len)], % Start the search MaxLen = _, Continue := true, foreach(Len in 2..Words.len, break(Continue == false)) if play1(Words2,Starts,Len,_List) then MaxLen := Len else Continue := false end end, println(maxLen=MaxLen), % And present the result. println("\nGet some (5) solutions:"), get_some_solutions(Words2, Starts, MaxLen,5), println("\nNnumber of optimal solutions:"), NumSols = count_all(play1(Words2,Starts,MaxLen,_List)), println(num_sols=NumSols), nl. % Check if it's possible to create a list of length Len. play1(Words, Starts, Len, LLFL) :- LLFL1 = new_list(Len), select(LLFL1[1], Words, Rest), C = 2, while (C <= Len) Among = Starts.get(LLFL1[C-1]), Among != [], select(Word,Among,Rest2), not membchk(Word,LLFL1[1..C-1]), LLFL1[C] := Word, Rest := Rest2, C := C + 1 end, LLFL = LLFL1. % Print NumSols solutions get_some_solutions(Words,Starts,FoundLen,NumSols) => Map = get_global_map(), Map.put(count,1), play1(Words, Starts, FoundLen, LLFL), println(LLFL), C = Map.get(count), if C < NumSols then Map.put(count,C+1), fail end. % qsort(List, SortFunction) % returns a sorted list according to the sort function SortFunction. qsort([],_F) = []. qsort([H\|T],F) = qsort([E : E in T, call(F,E,H)], F) ++ [H] ++ qsort([E : E in T, not call(F,E,H)],F). % Sort according to length sort_len((_K1=V1),(_K2=V2)) :- V1.len >= V2.len. words(Words) => Words = [ "audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask" ].</syntaxhighlight> {{out}} <pre>maxLen = 23 Get some (5) solutions: [machamp,petilil,landorus,scrafty,yamask,kricketune,emboar,registeel,loudred,darmanitan,nosepass,simisear,relicanth,heatmor,rufflet,trapinch,haxorus,seaking,girafarig,gabite,exeggcute,emolga,audino] [machamp,petilil,landorus,scrafty,yamask,kricketune,emboar,registeel,loudred,darmanitan,nosepass,simisear,rufflet,trapinch,heatmor,relicanth,haxorus,seaking,girafarig,gabite,exeggcute,emolga,audino] [machamp,petilil,landorus,scrafty,yamask,kricketune,emboar,relicanth,haxorus,simisear,rufflet,trapinch,heatmor,registeel,loudred,darmanitan,nosepass,seaking,girafarig,gabite,exeggcute,emolga,audino] [machamp,petilil,landorus,scrafty,yamask,kricketune,emboar,relicanth,heatmor,registeel,loudred,darmanitan,nosepass,simisear,rufflet,trapinch,haxorus,seaking,girafarig,gabite,exeggcute,emolga,audino] [machamp,petilil,landorus,scrafty,yamask,kricketune,emboar,relicanth,heatmor,rufflet,trapinch,haxorus,simisear,registeel,loudred,darmanitan,nosepass,seaking,girafarig,gabite,exeggcute,emolga,audino] Nnumber of optimal solutions: num_sols = 1248</pre> =={{header\|PicoLisp}}== <~~lang~~syntaxhighlight ~~PicoLisp~~lang="picolisp">(de pokemonChain (File) (let Names (make (in File (while (read) (link @)))) (for Name Names Line 1,089 ⟶ 3,532: (setq Res Lst) ) (mapc recurse (val Name) (circ Lst)) ) ) ) ) (flip Res) ) ) )</~~lang~~syntaxhighlight> Test: <pre> Line 1,098 ⟶ 3,541: : (length @) -> 23 </pre> =={{header\|Prolog}}== Works with SWI-Prolog and module '''lambda.pl''' written by '''Ulrich Neumerkel''' found there http://www.complang.tuwien.ac.at/ulrich/Prolog-inedit/lambda.pl <syntaxhighlight lang="prolog">:- use_module(library(lambda)). :- dynamic res/3. last_first(Len, Nb, L) :- retractall(res(_,_,_)), assert(res(0, 0, [])), % compute all the lists of connected words last_first, res(Len, Nb, L1), % to have only the words maplist(\X^Y^(X = [Y, _, _]), L1, L). % create the lists of connected words (initiate the first word) last_first :- init(L), forall(select(Word, L, L1), \+lance_p([Word \| L1])). % compute all the lists beginning with a word % memorize the longest lance_p(L) :- p(LF, L), retract(res(Len, Nb, Lst)), length(LF, Len1), ( Len1 > Len -> assert(res(Len1, 1, LF)) ; Len1 = Len -> Nb1 is Nb + 1, assert(res(Len, Nb1, Lst)) ; assert(res(Len, Nb, Lst))), fail. % describe the property of the list of connected words p([A \| T], [A \| L]) :- select(B, L, L1), p0(A,B), T = [B \| T1], p([B \| T1], [B \| L1]). % a list with one element is valid p([_], _). % are words conected ? p0([_, _, W], [_, W, _]). % each word is associated with its first and last letters % audino --> [audino, a, o] init(L) :- L0 = [ audino, bagon, baltoy, banette, bidoof, braviary, bronzor, carracosta, charmeleon, cresselia, croagunk, darmanitan, deino, emboar, emolga, exeggcute, gabite, girafarig, gulpin, haxorus, heatmor, heatran, ivysaur, jellicent, jumpluff, kangaskhan, kricketune, landorus, ledyba, loudred, lumineon, lunatone, machamp, magnezone, mamoswine, nosepass, petilil, pidgeotto, pikachu, pinsir, poliwrath, poochyena, porygon2, porygonz, registeel, relicanth, remoraid, rufflet, sableye, scolipede, scrafty, seaking, sealeo, silcoon, simisear, snivy, snorlax, spoink, starly, tirtouga, trapinch, treecko, tyrogue, vigoroth, vulpix, wailord, wartortle, whismur, wingull, yamask], maplist(init_, L0, L). % audino --> [audino, a, o] init_(W, [W, F, L]) :- first_letter(W, F), last_letter(W, L). first_letter(A, F) :- atom_chars(A, [F \| _]). last_letter(A, L) :- atom_chars(A, LC), reverse(LC, [L \| _]). </syntaxhighlight> Output : <pre>?- time(last_first(Len, Nb, L)). % 592,161,339 inferences, 125.690 CPU in 128.264 seconds (98% CPU, 4711284 Lips) Len = 23, Nb = 1248, L = [machamp,petilil,landorus,scrafty,yamask,kricketune,emboar,registeel,loudred,darmanitan,nosepass,simisear,relicanth,heatmor,rufflet,trapinch,haxorus,seaking,girafarig,gabite,exeggcute,emolga,audino]. </pre> =={{header\|Python}}== <~~lang~~syntaxhighlight lang="python">from collections import defaultdict def order_words(words): Line 1,147 ⟶ 3,677: l = llfl(pokemon) for i in range(0, len(l), 8): print(' '.join(l[i:i+8])) print(len(l))</~~lang~~syntaxhighlight> ;Sample output <pre>machamp pinsir relicanth heatmor remoraid darmanitan nosepass snivy ~~<pre>audino bagon baltoy banette bidoof braviary bronzor carracosta~~ yamask kricketune exeggcute emboar registeel landorus simisear rufflet ~~charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute~~ trapinch haxorus seaking girafarig gabite emolga audino ~~gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent~~ 23</pre> ===Alternative version=== Adapted from the D version. This uses Psyco. <~~lang~~syntaxhighlight lang="python">import psyco nsolutions = 0 Line 1,230 ⟶ 3,760: psyco.full() main()</~~lang~~syntaxhighlight> Output: <pre>Maximum path length: 23 Line 1,240 ⟶ 3,770: emolga audino</pre> Run time: about 0.44 seconds with Psyco and Python 2.6.6. =={{header\|Racket}}== This is a naive solution, which works fast enough as is (takes about 5 seconds on an old machine): <syntaxhighlight lang="racket">#lang racket (define names " audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask") (struct word (first last string) #:prefab) (define words (for/list ([str (string-split names)]) (word (string->symbol (substring str 0 1)) (string->symbol (substring str (sub1 (string-length str)))) str))) (define (find-longest last words) (for/fold ([best '()]) ([w (in-list words)] #:when (or (not last) (eq? last (word-first w)))) (define long (cons w (find-longest (word-last w) (remq w words)))) (if (> (length long) (length best)) long best))) (define longest (find-longest #f words)) (printf "Longest chain found has ~a words:\n ~a\n" (length longest) (string-join (map word-string longest) " -> ")) </syntaxhighlight> {{out}} <pre> Longest chain found has 23 words: machamp -> petilil -> landorus -> scrafty -> yamask -> kricketune -> emboar -> registeel -> loudred -> darmanitan -> nosepass -> simisear -> relicanth -> heatmor -> rufflet -> trapinch -> haxorus -> seaking -> girafarig -> gabite -> exeggcute -> emolga -> audino </pre> This is a (probably over-)complex version which tries to construct longest chains using three different combination/relinking functions. Not that the definiton of `word` is slightly different here. <syntaxhighlight lang="racket">#lang racket (require "pokemon-names.rkt") ;;; Some fundamentals... finding the first (henceforth referred to as "a") and last ("z") ;;; letters of a word can be computationally intensive... look at symbol->word, and you'll ;;; see that when we have to deal with a name like: "Mime Jr.", the last alphabetic letter ;;; is not the last character. And the first and last characters (at least) have to be ;;; case-normalised so they can be compared with char=? (it's not particulary helpful to ;;; map them down to integer character codes; we'll want to see them for debugging). (define-struct word (sym char-a char-z) #:prefab) ;;; names are input as symbols both for ease of comparsion, and because it's easier to type (define (symbol->word sym) (let ((str (symbol->string sym)) (chrs (string->list str)) (fst (for/first ((c chrs) #:when (char-alphabetic? c)) (char-downcase c))) (lst (for/last ((c chrs) #:when (char-alphabetic? c)) (char-downcase c)))) (make-word sym fst lst))) ;;; We're sometimes not interested in debugging a chain of; just in knowing how long it is ;;; and what its extreme characters are. This does the trick. (define (summarise-chain c) (format "(~a.~a.~a)" (word-char-a (first c)) (sub1 (length c)) (word-char-z (last c)))) ;; Test the above (run `raco test last_letter-first_letter-common.rkt`) (define-syntax-rule (hash-set-or-remove hsh key val remove-pred?) (let ((v val)) (if (remove-pred? v) (hash-remove hsh key) (hash-set hsh key v)))) (define-syntax-rule (find-a-in-chain-pool chains a dont-match-sym) (for/first ((c chains) (i (in-naturals)) ;; usually need an index for regenerating chains pool ;; a word can only exist in one chain, so this compares chains' identities #:unless (eq? (word-sym (first c)) dont-match-sym) #:when (char=? (word-char-a (first c)) a)) (cons i c))) (define-syntax-rule (copy-list-ignoring-indices lst i1 i2) (for/list ((idx (in-naturals)) (e (in-list lst)) #:unless (= idx i1) #:unless (= idx i2)) e)) ;; Simple ... find a chain that can be put on the end of c... append it, and ;; reiterate (define (append-ab..bz-chains chain chain-idx chains) (let* ((a1.chain-a (find-a-in-chain-pool chains (word-char-z (last chain)) (word-sym (first chain))))) (and a1.chain-a (let ((a1.chain-idx (first a1.chain-a)) (a1.chain-chain (rest a1.chain-a))) (cons (append chain a1.chain-chain) (copy-list-ignoring-indices chains chain-idx a1.chain-idx)))))) ;; If chain has an a..a loop in it, then we see if we can take that loop, and ;; place it in a longer chain at a point where a is used. ;; ;; `chain` is the shorter chain containing the loop (define (merge-chain-into-chain-accepting-a..a-in-chain chain chain-idx chains) ;; for a..a loops in chain, returns a hash from the looped char, to the longest ;; found loop (define (find-a..a-loops chain) (let ((chain-length (length chain))) (for/fold ((hsh (hash))) ((sub-range-start (in-range chain-length)) (aa (in-value (word-char-a (list-ref chain sub-range-start)))) (sub-range-end (in-range sub-range-start chain-length)) #:when (eq? aa (word-char-z (list-ref chain sub-range-end))) (range-length (in-value (add1 (- sub-range-end sub-range-start))))) (hash-update hsh aa (lambda (longest-range) (if (and longest-range (> (third longest-range) range-length)) longest-range (list sub-range-start sub-range-end range-length))) #f)))) (let ((chain-first-name (word-sym (first chain))) (chain-length (length chain)) (a..a-list (sort (hash->list (find-a..a-loops chain)) > #:key third))) (for/first (((chain2 chain2-idx) (in-parallel (in-list chains) (in-naturals))) #:unless (eq? chain-first-name (word-sym (car chain2))) (chain2-length (in-value (length chain2))) #:when (>= chain2-length chain-length) ; only move the largest a..a-subchain into a larger chain (a..a (in-list a..a-list)) ((insertion-point-word insertion-point-idx) (in-parallel (in-list chain2) (in-naturals))) #:when (eq? (car a..a) (word-char-a insertion-point-word))) (let ((new-chain (append (take chain (second a..a)) (drop chain (add1 (third a..a))))) (a..a-chain (take (drop chain (second a..a)) (fourth a..a))) (new-chain2 (append (take chain2 insertion-point-idx) a..a-chain (drop chain2 insertion-point-idx)))) (let ((new-chains (copy-list-ignoring-indices chains chain-idx chain2-idx))) (if (null? new-chain) (cons new-chain2 new-chains) (cons new-chain (cons new-chain2 new-chains)))))))) ;; this is a bit more combinatorially intensive... for all c2, substitute a ;; subrange in c2 that is longer than an equivalent subrange in c (define (merge-subranges-of-chains-into-chain chain chain-idx chains) (let ((chain-first-name (word-sym (first chain))) (chain-length (length chain)) (chain-first-a (word-char-a (first chain))) (chain-last-z (word-char-z (last chain)))) (for/first ; try to replace a subrange in c2 with c (((chain2 chain2-idx) (in-parallel (in-list chains) (in-naturals))) (chain2-length (in-value (length chain2))) #:unless (eq? chain-first-name (word-sym (car chain2))) (c2-sub-range-start (in-range chain2-length)) (c2-sub-range-end (in-range c2-sub-range-start (min chain2-length (+ c2-sub-range-start chain-length)))) #:unless (and (= c2-sub-range-start 0) (= c2-sub-range-end (sub1 chain2-length))) #:when (or (zero? c2-sub-range-start) (eq? (word-char-a (list-ref chain2 c2-sub-range-start)) chain-first-a)) #:when (or (= (sub1 chain2-length) c2-sub-range-end) (eq? (word-char-z (list-ref chain2 c2-sub-range-end)) chain-last-z)) (c2-sub-range-len (in-value (add1 (- c2-sub-range-end c2-sub-range-start)))) #:when (> chain-length c2-sub-range-len) (c2-sub-range (in-value (take (drop chain2 c2-sub-range-start) c2-sub-range-len))) (new-c2 (in-value (append (take chain2 c2-sub-range-start) chain (drop chain2 (add1 c2-sub-range-end)))))) (cons c2-sub-range ; put the subrange back into the chains pool (cons new-c2 ; put the modified onto the chains pool (copy-list-ignoring-indices chains chain-idx chain2-idx)))))) (define (longest-chain/constructive names #:known-max (known-max +inf.0)) (define names-list (map symbol->word names)) (define (link-chains chains) (let ((new-chains (for/first (((chain chain-idx) (in-parallel (in-list chains) (in-naturals))) (new-chains (in-value (or (append-ab..bz-chains chain chain-idx chains) (merge-chain-into-chain-accepting-a..a-in-chain chain chain-idx chains) (merge-subranges-of-chains-into-chain chain chain-idx chains)))) #:when new-chains) new-chains))) (if new-chains (link-chains new-chains) chains))) (define (keep-trying (run-count 0) (linked-chains (link-chains (map list (shuffle names-list)))) (previous-best null) (previous-best-length 0) (this-run-best-length #f)) (let* ((longest-chain (argmax length linked-chains)) (longest-chain-len (length longest-chain)) (new-best? (< previous-best-length longest-chain-len)) (best-length (if new-best? longest-chain-len previous-best-length)) (best (if new-best? longest-chain previous-best))) (when new-best? (newline) (displayln (list (map word-sym longest-chain) longest-chain-len)) (flush-output)) (if (and new-best? (>= best-length known-max)) (displayln "terminating: known max reached or exceeded") (begin (when (zero? (modulo (add1 run-count) 250)) (eprintf ".") (flush-output (current-error-port))) (if (= run-count 1000) (keep-trying 0 (link-chains (map list (shuffle names-list))) best best-length 0) (let ((sorted-linked-chains (sort linked-chains #:key length >))) (keep-trying (if new-best? 0 (add1 run-count)) (link-chains (cons (car sorted-linked-chains) (map list (shuffle (apply append (cdr sorted-linked-chains)))))) best best-length (and this-run-best-length (if new-best? #f (if (< this-run-best-length longest-chain-len) (begin (eprintf ">~a" longest-chain-len) (flush-output (current-error-port)) longest-chain-len) this-run-best-length)))))))))) (keep-trying)) (time (longest-chain/constructive names-70 #:known-max 23)) (longest-chain/constructive names-646)</syntaxhighlight> Run with ''racket -t last_letter-first_letter-randomised.rkt 2>&1'', to redirect standard error to standard out. {{out}} <pre> ((machamp petilil landorus seaking girafarig gabite exeggcute emboar relicanth heatran nosepass simisear registeel loudred deino) 15) ((machamp petilil landorus seaking girafarig gabite exeggcute emboar relicanth haxorus snivy yamask kangaskhan nosepass simisear registeel lunatone emolga audino) 19) ((machamp petilil landorus seaking girafarig gabite exeggcute emboar rufflet trapinch heatmor relicanth haxorus snivy yamask kangaskhan nosepass simisear registeel lunatone emolga audino) 22) ....>10>17>19....>14>17>20>21....>15>18>21>22....>16>17>22....>15>17>18>21....>19>20....>16>18>20>22....>14>21 ((machamp petilil landorus seaking girafarig gabite emboar rufflet trapinch heatmor relicanth haxorus simisear registeel loudred darmanitan nosepass starly yamask kricketune exeggcute emolga audino) 23) terminating: known max reached or exceeded cpu time: 24077 real time: 24070 gc time: 36</pre> As an aside... I've had this take 40 s; and I've had it run in 35 ms. It really is the luck of the draw! </pre> ((Jellicent Tangrowth Hippopotas Slowking Gyarados Spiritomb Breloom Mandibuzz Zweilous Shellos Stoutland Deoxys Swoobat Togekiss Seedot Toxicroak Krokorok Kabutops Seadra Anorith Heracross Slakoth Haxorus Shelmet Tauros Skiploom Manectric Castform Milotic Chingling Golem Mothim Meganium Metapod Ducklett Tornadus Swellow Whismur Rufflet Taillow Wormadam Medicham Mismagius Snubbull Latias Solosis Sandshrew Woobat Teddiursa Abomasnow Wingull Lapras Seel Lillipup Paras Sandslash Hoppip Prinplup Piplup Petilil Lickilicky Yanmega Abra Ariados Solrock Klink Kingler Relicanth Hariyama Altaria Azumarill Luvdisc Charmander Rotom Maractus Skuntank Kirlia Azelf Farfetch'd Delibird Dratini Illumise Exploud Diglett Torkoal Lampent Turtwig Girafarig Golbat Tepig Grumpig Granbull Larvesta Azurill Loudred Dialga Amoonguss Sigilyph Herdier Rampardos Seaking Golett Timburr Raichu Umbreon Noctowl Latios Sawk Kyurem Miltank Klinklang Gorebyss Slaking Gliscor Rhyhorn Nidorina Alakazam Machamp Pidgeot Trubbish Hitmontop Politoed Dewgong Gardevoir Regigigas Swampert Tympole Electrode Exeggcute Eelektrik Kingdra Accelgor Remoraid Dewott Tentacool Litwick Koffing Gigalith Hypno Octillery Yanma Arcanine Elekid Dusknoir Reshiram Mesprit Tropius Swalot Tranquill Luxray Yamask Kyogre Eevee Electivire Emolga Alomomola Ampharos Spinarak Kricketune Exeggutor Roselia Arbok Krookodile Escavalier Rayquaza Aron Ninetales Serperior Registeel Lileep Patrat Throh Hitmonlee Espeon Nidoqueen Ninjask Kakuna Axew Wigglytuff Frillish Houndour Regice Eelektross Swinub Budew Whiscash Hoothoot Torterra Aipom Mareep Poliwag Grimer Roggenrola Armaldo Omastar Rhyperior Ralts Scolipede Excadrill Luxio Oshawott Togetic Crawdaunt Torchic Cofagrigus Shroomish Houndoom Marill Larvitar Raticate Electrike Ekans Starmie Emboar Regirock Karrablast Tangela Aerodactyl Lairon Nidoran Natu Unfezant Trapinch Horsea Archen Nidoran Nosepass Staravia Ambipom Murkrow Weezing Gothita Absol Lotad Darmanitan Nincada Arceus Spheal Lilligant Tynamo Omanyte Elgyem Mew Watchog Golduck Kabuto Oddish Ho-Oh Heatran Nidoking Golurk Klang Garchomp Porygon-Z Zekrom Meowth Hippowdon Nuzleaf Feraligatr Rapidash Haunter Reuniclus Seviper Raikou Ursaring Glalie Entei Igglybuff Froslass Spearow Wailord Duskull Ludicolo Onix Xatu Unown Numel Landorus Seismitoad Deerling Grovyle Empoleon Nidorino) 283)</pre> '''...''' <pre>((Voltorb Beartic Croconaw Wynaut Tangrowth Hippopotas Smoochum Moltres Shuppet Thundurus Slowking Gyarados Spiritomb Breloom Mandibuzz Zweilous Shellos Stoutland Deoxys Swoobat Togekiss Seedot Toxicroak Krokorok Kabutops Snorunt Tirtouga Anorith Heracross Slakoth Haxorus Shelmet Tauros Skiploom Manectric Castform Milotic Chingling Golem Mothim Meganium Metapod Ducklett Tornadus Swellow Whismur Rufflet Taillow Wormadam Medicham Mismagius Snubbull Latias Solosis Sandshrew Woobat Teddiursa Abomasnow Wingull Lapras Seel Lillipup Paras Sandslash Hoppip Prinplup Piplup Probopass Stunfisk Krabby Yanmega Abra Ariados Solrock Klink Kingler Relicanth Hariyama Altaria Azumarill Luvdisc Chatot Tyranitar Rotom Maractus Skuntank Kirlia Azelf Farfetch'd Delibird Dratini Ivysaur Riolu Uxie Electabuzz Zapdos Sawsbuck Kyogre Exploud Diglett Torkoal Lampent Turtwig Girafarig Golbat Tepig Grumpig Granbull Larvesta Azurill Loudred Dialga Amoonguss Sigilyph Herdier Rampardos Seaking Golett Timburr Raichu Umbreon Noctowl Latios Sawk Kyurem Miltank Klinklang Gorebyss Slaking Gigalith Huntail Ledyba Aggron Nidorina Alakazam Machamp Pidgeot Trubbish Hitmontop Politoed Dewgong Gardevoir Regigigas Swampert Tentacruel Lickitung Glameow Whirlipede Electrode Exeggcute Eelektrik Kingdra Accelgor Remoraid Dewott Tentacool Litwick Koffing Gloom Marshtomp Psyduck Kadabra Articuno Octillery Yanma Arcanine Elekid Dusknoir Reshiram Mesprit Tropius Swalot Tranquill Luxray Yamask Kricketot Tyrogue Eevee Electivire Emolga Alomomola Ampharos Sentret Togepi Infernape Exeggutor Roselia Arbok Krookodile Escavalier Rayquaza Aron Ninetales Serperior Registeel Lileep Patrat Throh Honchkrow Wobbuffet Totodile Espeon Nidoqueen Ninjask Kakuna Axew Wigglytuff Frillish Houndour Regice Eelektross Swinub Budew Whiscash Hoothoot Torterra Aipom Mareep Poliwag Grimer Roggenrola Armaldo Omastar Rhyperior Ralts Surskit Tympole Excadrill Lugia Audino Oshawott Togetic Crawdaunt Torchic Cofagrigus Shroomish Houndoom Mudkip Ponyta Archeops Spinarak Kricketune Electrike Ekans Simisear Raticate Emboar Regirock Karrablast Tangela Aerodactyl Liepard Dusclops Spoink Kecleon Nidoran Natu Unfezant Trapinch Horsea Archen Nidoran Nosepass Snover Rattata Ambipom Murkrow Weezing Gothita Absol Lotad Durant Terrakion Nincada Arceus Spheal Lilligant Tynamo Omanyte Elgyem Mew Watchog Golduck Kabuto Oddish Ho-Oh Heatran Nidoking Golurk Klang Garchomp Porygon-Z Zekrom Magikarp Pawniard Deerling Gurdurr Rhydon Nuzleaf Foongus Shellder Rapidash Haunter Reuniclus Seviper Raikou Ursaring Garbodor Roserade Entei Igglybuff Froslass Spearow Wailord Duskull Ludicolo Onix Xatu Unown Numel Landorus Seismitoad Drifblim Machop Palpitoad Darkrai Illumise Empoleon Nidorino) 329)</pre> Never terminates. The longest chain I have found (so far?) is 333 long: <pre>((Voltorb Breloom Medicham Machop Piplup Palpitoad Deerling Golett Turtwig Glameow Wingull Lilligant Timburr Registeel Lotad Duskull Latias Serperior Reuniclus Spinarak Krokorok Klinklang Golem Mew Whiscash Huntail Lugia Accelgor Rattata Aerodactyl Luvdisc Chingling Grumpig Garchomp Prinplup Petilil Loudred Ducklett Tornadus Spearow Whimsicott Tangrowth Hoothoot Tentacruel Lampent Togekiss Skiploom Marshtomp Patrat Thundurus Solosis Sneasel Lillipup Poliwhirl Lapras Sandslash Honchkrow Wobbuffet Torkoal Latios Slaking Gligar Rampardos Shellos Sentret Tropius Sigilyph Herdier Remoraid Dusclops Stoutland Drilbur Reshiram Misdreavus Slowking Golduck Klink Koffing Gyarados Shuppet Tauros Swellow Wynaut Torchic Castform Maractus Spiritomb Bayleef Furret Tangela Altaria Aipom Murkrow Wigglytuff Forretress Spheal Lickitung Gigalith Heracross Snorunt Totodile Exeggcute Electrode Ekans Solrock Klang Girafarig Gorebyss Swalot Trapinch Ho-Oh Hitmontop Porygon-Z Zapdos Shroomish Houndour Relicanth Hoppip Poliwrath Houndoom Mareep Poliwag Golurk Kirlia Axew Wormadam Mandibuzz Zweilous Swinub Beldum Manectric Cherrim Moltres Staraptor Rayquaza Azurill Lairon Nidoqueen Noctowl Leavanny Yamask Kricketune Eevee Escavalier Rufflet Torterra Archen Ninjask Kakuna Absol Lunatone Excadrill Ludicolo Octillery Yanma Archeops Spoink Kabuto Onix Xatu Unown Nidoran Ninetales Sawsbuck Kyurem Magikarp Politoed Dewott Trubbish Hippopotas Seel Linoone Empoleon Nincada Amoonguss Swoobat Teddiursa Audino Oshawott Tepig Gloom Metagross Shelmet Tentacool Larvesta Ariados Skorupi Illumise Exploud Durant Tynamo Omastar Roggenrola Arbok Kricketot Taillow Weezing Grimer Rhyperior Rapidash Haxorus Skuntank Kingdra Alomomola Azelf Ferroseed Drifblim Marowak Kingler Roselia Azumarill Lanturn Natu Ursaring Golbat Toxicroak Kecleon Numel Landorus Samurott Togepi Infernape Electrike Electivire Electabuzz Zekrom Metang Galvantula Arceus Seedot Tirtouga Aron Nosepass Seismitoad Dialga Articuno Oddish Horsea Alakazam Meganium Marill Liepard Deoxys Smoochum Mudkip Probopass Stunfisk Krookodile Elekid Delibird Dratini Igglybuff Foongus Swampert Tyranitar Raikou Uxie Eelektross Slakoth Hariyama Abra Anorith Haunter Raichu Umbreon Nidorina Aggron Nuzleaf Floatzel Litwick Kyogre Exeggutor Raticate Emboar Regirock Kabutops Sandshrew Watchog Gurdurr Roserade Entei Ivysaur Regice Emolga Abomasnow Wailord Diglett Tyrogue Espeon Nidoran Nidoking Granbull Ledyba Arcanine Elgyem Mothim Mismagius Sawk Kadabra Ampharos Snubbull Larvitar Riolu Unfezant Togetic Charizard Dewgong Gothita Ambipom Machamp Paras Simisear Ralts Seaking Gliscor Rotom Milotic Cyndaquil Lileep Pawniard Dragonair Regigigas Surskit Tranquill Ledian Nidorino Omanyte Eelektrik Karrablast Throh Happiny Yanmega Armaldo) 333)</pre> '''File: pokemon-names.rkt''' <syntaxhighlight lang="racket">#lang racket (provide names-646 names-70) (define names-70 '(audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask)) ; If this were true, then the 2 would be ignored, which seems a bit wrong; so wordigy the "2" -> "two" (define Porygon2 (if #f 'Porygon2 'Porygon-two)) ; note that Porygon2 is used with a comma in the list below (define names-646 `(Bulbasaur Ivysaur Venusaur Charmander Charmeleon Charizard Squirtle Wartortle Blastoise Caterpie Metapod Butterfree Weedle Kakuna Beedrill Pidgey Pidgeotto Pidgeot Rattata Raticate Spearow Fearow Ekans Arbok Pikachu Raichu Sandshrew Sandslash Nidoran Nidorina Nidoqueen Nidoran Nidorino Nidoking Clefairy Clefable Vulpix Ninetales Jigglypuff Wigglytuff Zubat Golbat Oddish Gloom Vileplume Paras Parasect Venonat Venomoth Diglett Dugtrio Meowth Persian Psyduck Golduck Mankey Primeape Growlithe Arcanine Poliwag Poliwhirl Poliwrath Abra Kadabra Alakazam Machop Machoke Machamp Bellsprout Weepinbell Victreebel Tentacool Tentacruel Geodude Graveler Golem Ponyta Rapidash Slowpoke Slowbro Magnemite Magneton \|Farfetch'd\| Doduo Dodrio Seel Dewgong Grimer Muk Shellder Cloyster Gastly Haunter Gengar Onix Drowzee Hypno Krabby Kingler Voltorb Electrode Exeggcute Exeggutor Cubone Marowak Hitmonlee Hitmonchan Lickitung Koffing Weezing Rhyhorn Rhydon Chansey Tangela Kangaskhan Horsea Seadra Goldeen Seaking Staryu Starmie \|Mr. Mime\| Scyther Jynx Electabuzz Magmar Pinsir Tauros Magikarp Gyarados Lapras Ditto Eevee Vaporeon Jolteon Flareon Porygon Omanyte Omastar Kabuto Kabutops Aerodactyl Snorlax Articuno Zapdos Moltres Dratini Dragonair Dragonite Mewtwo Mew Chikorita Bayleef Meganium Cyndaquil Quilava Typhlosion Totodile Croconaw Feraligatr Sentret Furret Hoothoot Noctowl Ledyba Ledian Spinarak Ariados Crobat Chinchou Lanturn Pichu Cleffa Igglybuff Togepi Togetic Natu Xatu Mareep Flaaffy Ampharos Bellossom Marill Azumarill Sudowoodo Politoed Hoppip Skiploom Jumpluff Aipom Sunkern Sunflora Yanma Wooper Quagsire Espeon Umbreon Murkrow Slowking Misdreavus Unown Wobbuffet Girafarig Pineco Forretress Dunsparce Gligar Steelix Snubbull Granbull Qwilfish Scizor Shuckle Heracross Sneasel Teddiursa Ursaring Slugma Magcargo Swinub Piloswine Corsola Remoraid Octillery Delibird Mantine Skarmory Houndour Houndoom Kingdra Phanpy Donphan ,Porygon2 Stantler Smeargle Tyrogue Hitmontop Smoochum Elekid Magby Miltank Blissey Raikou Entei Suicune Larvitar Pupitar Tyranitar Lugia Ho-Oh Celebi Treecko Grovyle Sceptile Torchic Combusken Blaziken Mudkip Marshtomp Swampert Poochyena Mightyena Zigzagoon Linoone Wurmple Silcoon Beautifly Cascoon Dustox Lotad Lombre Ludicolo Seedot Nuzleaf Shiftry Taillow Swellow Wingull Pelipper Ralts Kirlia Gardevoir Surskit Masquerain Shroomish Breloom Slakoth Vigoroth Slaking Nincada Ninjask Shedinja Whismur Loudred Exploud Makuhita Hariyama Azurill Nosepass Skitty Delcatty Sableye Mawile Aron Lairon Aggron Meditite Medicham Electrike Manectric Plusle Minun Volbeat Illumise Roselia Gulpin Swalot Carvanha Sharpedo Wailmer Wailord Numel Camerupt Torkoal Spoink Grumpig Spinda Trapinch Vibrava Flygon Cacnea Cacturne Swablu Altaria Zangoose Seviper Lunatone Solrock Barboach Whiscash Corphish Crawdaunt Baltoy Claydol Lileep Cradily Anorith Armaldo Feebas Milotic Castform Kecleon Shuppet Banette Duskull Dusclops Tropius Chimecho Absol Wynaut Snorunt Glalie Spheal Sealeo Walrein Clamperl Huntail Gorebyss Relicanth Luvdisc Bagon Shelgon Salamence Beldum Metang Metagross Regirock Regice Registeel Latias Latios Kyogre Groudon Rayquaza Jirachi Deoxys Turtwig Grotle Torterra Chimchar Monferno Infernape Piplup Prinplup Empoleon Starly Staravia Staraptor Bidoof Bibarel Kricketot Kricketune Shinx Luxio Luxray Budew Roserade Cranidos Rampardos Shieldon Bastiodon Burmy Wormadam Mothim Combee Vespiquen Pachirisu Buizel Floatzel Cherubi Cherrim Shellos Gastrodon Ambipom Drifloon Drifblim Buneary Lopunny Mismagius Honchkrow Glameow Purugly Chingling Stunky Skuntank Bronzor Bronzong Bonsly \|Mime Jr.\| Happiny Chatot Spiritomb Gible Gabite Garchomp Munchlax Riolu Lucario Hippopotas Hippowdon Skorupi Drapion Croagunk Toxicroak Carnivine Finneon Lumineon Mantyke Snover Abomasnow Weavile Magnezone Lickilicky Rhyperior Tangrowth Electivire Magmortar Togekiss Yanmega Leafeon Glaceon Gliscor Mamoswine Porygon-Z Gallade Probopass Dusknoir Froslass Rotom Uxie Mesprit Azelf Dialga Palkia Heatran Regigigas Giratina Cresselia Phione Manaphy Darkrai Shaymin Arceus Victini Snivy Servine Serperior Tepig Pignite Emboar Oshawott Dewott Samurott Patrat Watchog Lillipup Herdier Stoutland Purrloin Liepard Pansage Simisage Pansear Simisear Panpour Simipour Munna Musharna Pidove Tranquill Unfezant Blitzle Zebstrika Roggenrola Boldore Gigalith Woobat Swoobat Drilbur Excadrill Audino Timburr Gurdurr Conkeldurr Tympole Palpitoad Seismitoad Throh Sawk Sewaddle Swadloon Leavanny Venipede Whirlipede Scolipede Cottonee Whimsicott Petilil Lilligant Basculin Sandile Krokorok Krookodile Darumaka Darmanitan Maractus Dwebble Crustle Scraggy Scrafty Sigilyph Yamask Cofagrigus Tirtouga Carracosta Archen Archeops Trubbish Garbodor Zorua Zoroark Minccino Cinccino Gothita Gothorita Gothitelle Solosis Duosion Reuniclus Ducklett Swanna Vanillite Vanillish Vanilluxe Deerling Sawsbuck Emolga Karrablast Escavalier Foongus Amoonguss Frillish Jellicent Alomomola Joltik Galvantula Ferroseed Ferrothorn Klink Klang Klinklang Tynamo Eelektrik Eelektross Elgyem Beheeyem Litwick Lampent Chandelure Axew Fraxure Haxorus Cubchoo Beartic Cryogonal Shelmet Accelgor Stunfisk Mienfoo Mienshao Druddigon Golett Golurk Pawniard Bisharp Bouffalant Rufflet Braviary Vullaby Mandibuzz Heatmor Durant Deino Zweilous Hydreigon Larvesta Volcarona Cobalion Terrakion Virizion Tornadus Thundurus Reshiram Zekrom Landorus Kyurem))</syntaxhighlight> =={{header\|Raku}}== (formerly Perl 6) A breadth-first search that uses disk files to avoid memory exhaustion. Each candidate sequence is encoded at one character per name, so to avoid reuse of names we merely have to make sure there are no repeat characters in our encoded string. (The encoding starts at ASCII space for the first name, so newline is not among the encoded characters.) <syntaxhighlight lang="raku" line>my @names = < audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask >; my @last = @names.map: {.substr(-1,1).ord } my @succs = [] xx 128; for @names.kv -> $i, $name { my $ix = $name.ord; # $name.substr(0,1).ord push @succs[$ix], $i; } my $OUT = open "llfl.new", :w orelse .die; $OUT.print: chr($_ + 32),"\n" for 0 ..^ @names; close $OUT; my $new = +@names; my $len = 1; while $new { say "Length { $len++ }: $new candidates"; shell 'mv llfl.new llfl.known'; my $IN = open "llfl.known" orelse .die; my $OUT = open "llfl.new", :w orelse .die; $new = 0; loop { my $cand = $IN.get // last; for @succs[@last[$cand.ord - 32]][] -> $i { my $ic = chr($i + 32); next if $cand ~~ /$ic/; $OUT.print: $ic,$cand,"\n"; $new++; } } $IN.close; $OUT.close; } my $IN = open "llfl.known" orelse .die; my $eg = $IN.lines.pick; say "Length of longest: ", $eg.chars; say join ' ', $eg.ords.reverse.map: { @names[$_ - 32] }</syntaxhighlight> {{out}} <pre>Length 1: 70 candidates Length 2: 172 candidates Length 3: 494 candidates Length 4: 1288 candidates Length 5: 3235 candidates Length 6: 7731 candidates Length 7: 17628 candidates Length 8: 37629 candidates Length 9: 75122 candidates Length 10: 139091 candidates Length 11: 236679 candidates Length 12: 367405 candidates Length 13: 516210 candidates Length 14: 650916 candidates Length 15: 733915 candidates Length 16: 727566 candidates Length 17: 621835 candidates Length 18: 446666 candidates Length 19: 260862 candidates Length 20: 119908 candidates Length 21: 40296 candidates Length 22: 10112 candidates Length 23: 1248 candidates Length of longest: 23 machamp petilil loudred darmanitan nosepass simisear rufflet trapinch heatmor registeel landorus starly yamask kricketune exeggcute emboar relicanth haxorus seaking girafarig gabite emolga audino</pre> =={{header\|REXX}}== {{trans\|ooRexx}} ===brute force version=== (This program is modeled after the ooRexx version, but with a fixed bug.) <br><br>This REXX version allows a limit on the word scan (very useful for testing and debugging), and <br>also has various speed optimizations. <syntaxhighlight lang="rexx">/REXX program finds the longest path of word's last─letter ───► first─letter. / @='audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan', 'deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent', 'jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine', 'nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth', 'remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink', 'starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask' #= words(@); ig= 0; !.= 0; @.= /nullify array and the longest path. / parse arg limit .; if limit\=='' then #=limit /allow user to specify a scan limit. / call build@ /build a stemmed array from the @ list/ do v=# by -1 for # /scrub the @ list for unusable words. / parse var @.v F 2 '' -1 L /obtain first and last letter of word./ if !.1.F>1 \| !.9.L>1 then iterate /is this a dead word?/ say 'ignoring dead word:' @.v; ig= ig + 1; @= delword(@, v, 1) end /v/ /delete dead word from @ ──┘ / $$$= /nullify the possible longest path. / if ig\==0 then do; call build@; say; say 'ignoring' ig "dead word"s(ig).; say end MP= 0; MPL= 0 /the initial Maximum Path Length. / do j=1 for # / ─ ─ ─ / parse value @.1 @.j with @.j @.1; call scan $$$, 2 parse value @.1 @.j with @.j @.1 end /j/ g= words($$$) say 'Of' # "words," MP 'path's(MP) "have the maximum path length of" g'.' say; say 'One example path of that length is: ' word($$$, 1) do m=2 to g; say left('', 36) word($$$, m) end // exit 0 /stick a fork in it, we're all done. / /──────────────────────────────────────────────────────────────────────────────────────/ s: if arg(1)==1 then return arg(3); return word( arg(2) 's', 1) /a pluralizer./ /──────────────────────────────────────────────────────────────────────────────────────/ build@: do i=1 for #; @.i=word(@, i) /build a stemmed array from the list. / F= left(@.i, 1); !.1.F= !.1.F + 1 /F: 1st char; !.1.F=count of 1st char/ L=right(@.i, 1); !.9.L= !.9.L + 1 /L: last " !.9.L= " " last " / end /i/; return /──────────────────────────────────────────────────────────────────────────────────────/ scan: procedure expose @. # !. $$$ MP MPL; parse arg $$$,!; p=! - 1 parse var @.p '' -1 LC /obtain last character of previous @. / if !.1.LC==0 then return /is this a dead─end word? / / [↓] PARSE obtains first char of @.i/ do i=! to #; parse var @.i p 2 /scan for the longest word path. / if p==LC then do /is the first─character ≡ last─char? / if !==MPL then MP= MP+1 /bump the Maximum Paths Counter. / else if !>MPL then do; $$$=@.1 /rebuild. / do n=2 for !-2; $$$=$$$ @.n end /n/ $$$=$$$ @.i /add last./ MP=1; MPL=! /new path./ end parse value @.! @.i with @.i @.!; call scan $$$, !+1 parse value @.! @.i with @.i @.! end end /i/; return /exhausted this particular scan. /</syntaxhighlight> {{out\|output\|text=  when using the default input:}} <pre> Of 70 words, 1248 paths have the maximum path length of 23. One example path of that length is: machamp petilil landorus scrafty yamask kricketune emboar registeel loudred darmanitan nosepass simisear relicanth heatmor rufflet trapinch haxorus seaking girafarig gabite exeggcute emolga audino </pre> ===optimized version=== This optimized version has two major improvements: ::   removes dead words (words that cannot be used in a path) ::*   stops scanning when a dead-end word is encountered. With the full list of words being used, there are no dead words   (but there are when a limit is used to shorten the list). <br>In the   '''scan'''   subroutine, a check is made to see if the word being used is a dead-end word, and if so, the rest of <br>the recursive scan is aborted and the the next word is scanned. <br><br>The optimized version is around   '''25%'''   faster than the brute-force version. <syntaxhighlight lang="rexx">/REXX program finds the longest path of word's last─letter ───► first─letter. / @='audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan', 'deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent', 'jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine', 'nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth', 'remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink', 'starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask' #= words(@); @.=; @s=@.; ig=0; og=0; !.=0 /nullify array and the longest path. / parse arg limit .; if limit\=='' then #= limit /allow user to specify a scan limit. / call build@ /build a stemmed array from the @ list/ do v=# by -1 for # /scrub the @ list for unusable words. / parse var @.v F 2 '' -1 L /obtain first and last letter of word./ if !.1.F>1 \| !.9.L>1 then iterate /is this a dead word? / say 'ignoring dead word:' @.v; ig= ig + 1; @= delword(@, v, 1) end /v/ /delete dead word from @ ──┘ / #= words(@) /recalculate the number of words in @./ do v=# by -1 for # /scrub the @ list for stoppable words./ parse var @.v F 2 '' -1 L /obtain first and last letter of word./ if !.1.L>0 then iterate /is this a stop word? / if @.v\=='' then say 'removing stop word:' @.v og= og + 1; @= delword(@, v, 1); @s= @s @.v end /v/ /delete dead word from @ ──┘ / if og\==0 then do; call build@; say; say 'ignoring' og "stop word"s(og). say 'stop words: ' @s; say end $$$= /nullify the possible longest path. / MP= 0; MPL= 0 /the initial Maximum Path Length. / do j=1 for # /* ─ ─ ─ / parse value @.1 @.j with @.j @.1; call scan $$$, 2 parse value @.1 @.j with @.j @.1 end /j/ g= words($$$) say 'Of' # "words," MP 'path's(MP) "have the maximum path length of" g'.' say; say 'One example path of that length is: ' word($$$, 1) do m=2 to g; say left('', 36) word($$$, m) end /m/ exit /stick a fork in it, we're all done. / /──────────────────────────────────────────────────────────────────────────────────────/ s: if arg(1)==1 then return arg(3); return word( arg(2) 's', 1) /a pluralizer./ /──────────────────────────────────────────────────────────────────────────────────────/ build@: do i=1 for #; @.i= word(@, i) /build a stemmed array from the list. / F= left(@.i, 1); !.1.F= !.1.F + 1 /F: 1st char; !.1.F=count of 1st char/ L= right(@.i, 1); !.9.L= !.9.L + 1 /L: last " !.9.L= " " last " / end /i/; return /──────────────────────────────────────────────────────────────────────────────────────/ scan: procedure expose @. # !. $$$ MP MPL; parse arg $$$,!; p= ! - 1 parse var @.p '' -1 LC /obtain last character of previous @. / if !.1.LC==0 then return /is this a dead─end word? / / [↓] PARSE obtains first char of @.i/ do i=! to #; parse var @.i p 2 /scan for the longest word path. / if p==LC then do /is the first─character ≡ last─char? / if !==MPL then MP= MP+1 /bump the Maximum Paths Counter. / else if !>MPL then do; $$$= @.1 /rebuild. / do n=2 for !-2; $$$=$$$ @.n end /n/ $$$= $$$ @.i /add last./ MP=1; MPL=! /new path./ end parse value @.! @.i with @.i @.!; call scan $$$, !+1 parse value @.! @.i with @.i @.! end end /i/; return /exhausted this particular scan. /</syntaxhighlight> {{out\|output\|text=  is the same as the brute force version.}} <br><br> =={{header\|Ring}}== <syntaxhighlight lang="ring"> # Project : Last letter-first letter ready = [] names = ["audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"] strbegin = "gabite" strdir = "first" nr = 1 add(ready,strbegin) see strbegin + nl while true if strdir = "first" strc = right(strbegin, 1) flag = 1 nr = nr + 1 if nr <= len(names) if left(names[nr],1) = strc for n = 1 to len(ready) if names[nr] = ready[n] flag = 0 ok next if flag = 1 add(ready,names[nr]) see names[nr] + nl strbegin = names[nr] nr = 0 strdir = "last" loop ok ok ok else strc = right(strbegin, 1) flag = 1 nr = nr + 1 if nr <= len(names) if left(names[nr],1) = strc for n = 1 to len(ready) if names[nr] = ready[n] flag = 0 ok next if flag = 1 add(ready,names[nr]) see names[nr] + nl strbegin = names[nr] nr = 0 strdir = "first" loop ok ok ok ok end </syntaxhighlight> Output: <pre> gabite emboar registeel landorus sableye emolga audino </pre> =={{header\|Ruby}}== <syntaxhighlight lang="ruby">class LastL_FirstL def initialize(names) @names = names.dup @first = names.group_by {\|name\| name[0]} @sequences = [] end def add_name(seq) last_letter = seq[-1][-1] potentials = @first.include?(last_letter) ? (@first[last_letter] - seq) : [] if potentials.empty? @sequences << seq else potentials.each {\|name\| add_name(seq + [name])} end end def search @names.each {\|name\| add_name [name]} max = @sequences.max_by {\|seq\| seq.length}.length max_seqs = @sequences.select {\|seq\| seq.length == max} puts "there are #{@sequences.length} possible sequences" puts "the longest is #{max} names long" puts "there are #{max_seqs.length} such sequences. one is:" max_seqs.last.each_with_index {\|name, idx\| puts " %2d %s" % [idx+1, name]} end end names = %w{ audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask } lf = LastL_FirstL.new(names) lf.search</syntaxhighlight> outputs <pre>there are 2076396 possible sequences the longest is 23 names long there are 1248 such sequences. one is: 1 machamp 2 pinsir 3 rufflet 4 trapinch 5 heatmor 6 remoraid 7 darmanitan 8 nosepass 9 starly 10 yamask 11 kricketune 12 exeggcute 13 emboar 14 relicanth 15 haxorus 16 simisear 17 registeel 18 landorus 19 seaking 20 girafarig 21 gabite 22 emolga 23 audino</pre> =={{header\|Rust}}== {{trans\|Kotlin}} <syntaxhighlight lang="rust">/// # Panics /// /// If string is empty. fn first_char(string: &str) -> char { string.chars().next().unwrap() } /// # Panics /// /// If string is empty. fn first_and_last_char(string: &str) -> (char, char) { ( first_char(string), first_char(string.rmatches(\|_: char\| true).next().unwrap()), ) } struct Pokemon { name: &'static str, first: char, last: char, } impl Pokemon { fn new(name: &'static str) -> Pokemon { let (first, last) = first_and_last_char(name); Pokemon { name, first, last } } } #[derive(Default)] struct App { max_path_length: usize, max_path_length_count: usize, max_path_example: Vec<&'static str>, pokemon: Vec<Pokemon>, } impl App { fn search(&mut self, offset: usize) { if offset > self.max_path_length { self.max_path_length = offset; self.max_path_length_count = 1; } else if offset == self.max_path_length { self.max_path_length_count += 1; self.max_path_example.clear(); self.max_path_example.extend( self.pokemon[0..offset] .iter() .map(\|Pokemon { name, .. }\| name), ); } let last_char = self.pokemon[offset - 1].last; for i in offset..self.pokemon.len() { if self.pokemon[i].first == last_char { self.pokemon.swap(offset, i); self.search(offset + 1); self.pokemon.swap(offset, i); } } } } fn main() { let pokemon_names = [ "audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask", ]; let mut app = App { pokemon: pokemon_names .iter() .map(\|name\| Pokemon::new(name)) .collect(), ..App::default() }; for i in 0..app.pokemon.len() { app.pokemon.swap(0, i); app.search(1); app.pokemon.swap(0, i); } println!("Maximum path length: {}", app.max_path_length); println!("Paths of that length: {}", app.max_path_length_count); println!( "Example path of that length: {}", app.max_path_example.join(" "), ); } </syntaxhighlight> Recommend you run as `release` or at least with `opt-level=1` {{out}} <pre> Maximum path length: 23 Paths of that length: 1248 Example path of that length: machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> =={{header\|Scala}}== ===Naive=== <syntaxhighlight lang="scala">object LastLetterFirstLetterNaive extends App { def solve(names: Set[String]) = { def extend(solutions: List[List[String]]): List[List[String]] = { val more = solutions.flatMap{solution => val lastLetter = solution.head takeRight 1 (names -- solution).filter(_.take(1) equalsIgnoreCase lastLetter).map(_ :: solution) } if (more.isEmpty) solutions else extend(more) } extend(names.toList.map(List(_))).map(_.reverse) } val names70 = Set("audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask") val solutions = solve(names70) println(s"Maximum path length: ${solutions.head.length}") println(s"Paths of that length: ${solutions.size}") println("Example path of that length:") println(solutions.head.sliding(7,7).map(_.mkString(" ")).map(" "+_).mkString("\n")) }</syntaxhighlight> Output: <pre>Maximum path length: 23 Paths of that length: 1248 Example path of that length: machamp petilil loudred darmanitan nosepass snivy yamask kricketune emboar rufflet trapinch heatmor relicanth haxorus simisear registeel landorus seaking girafarig gabite exeggcute emolga audino</pre> ===With Lookup Table (Faster)=== <syntaxhighlight lang="scala">object LastLetterFirstLetterLookup extends App { def solve(names: Set[String]) = { val transitions = { val startsWith = names.groupBy(_.take(1).toLowerCase).withDefaultValue(Set.empty) names.map{name => name -> startsWith(name.takeRight(1).toLowerCase)}.toMap } def extend(solutions: List[List[String]]): List[List[String]] = solutions.flatMap{solution => (transitions(solution.head) -- solution).map(_ :: solution) } match { case Nil => solutions case more => extend(more) } extend(names.toList.map(List(_))).map(_.reverse) } val names70 = Set("audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask") val solutions = solve(names70) println(s"Maximum path length: ${solutions.head.length}") println(s"Paths of that length: ${solutions.size}") println("Example path of that length:") println(solutions.head.sliding(7,7).map(_.mkString(" ")).map(" "+_).mkString("\n")) }</syntaxhighlight> ===Parallelised With Lookup Table (Faster)=== <syntaxhighlight lang="scala">object LastLetterFirstLetterLookupParallel extends App { def solve(names: Set[String]) = { val transitions = { val startsWith = names.groupBy(_.take(1).toLowerCase).withDefaultValue(Set.empty) names.map{name => name -> startsWith(name.takeRight(1).toLowerCase)}.toMap } import scala.collection.parallel.immutable.ParSeq def extend(solutions: ParSeq[List[String]]): ParSeq[List[String]] = solutions.flatMap{solution => (transitions(solution.head) -- solution).map(_ :: solution) } match { case seq if seq.isEmpty => solutions case more => extend(more) } extend(names.toList.map(List(_)).par).map(_.reverse) } val names70 = Set("audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask") val solutions = solve(names70) println(s"Maximum path length: ${solutions.head.length}") println(s"Paths of that length: ${solutions.size}") println("Example path of that length:") println(solutions.head.sliding(7,7).map(_.mkString(" ")).map(" "+_).mkString("\n")) }</syntaxhighlight> =={{header\|Seed7}}== <syntaxhighlight lang="seed7">$ include "seed7_05.s7i"; var integer: maxPathLength is 0; var integer: maxPathLengthCount is 0; var string: maxPathExample is ""; var array string: names is [] ( "audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask"); const proc: recursive (in array string: part, in integer: offset) is func local var integer: index is 0; var char: lastChar is ' '; var string: tmp is ""; begin if pred(offset) > maxPathLength then maxPathLength := pred(offset); maxPathLengthCount := 1; elsif pred(offset) = maxPathLength then incr(maxPathLengthCount); maxPathExample := ""; for index range 1 to pred(offset) do if pred(index) rem 5 = 0 then maxPathExample &:= "\n "; else maxPathExample &:= " "; end if; maxPathExample &:= part[index]; end for; end if; lastChar := part[pred(offset)][length(part[pred(offset)])]; for index range offset to length(part) do if part[index][1] = lastChar then tmp := names[offset]; names[offset] := names[index]; names[index] := tmp; recursive(names, succ(offset)); names[index] := names[offset]; names[offset] := tmp; end if; end for; end func; const proc: main is func local var integer: index is 0; var string: tmp is ""; begin for index range 1 to length(names) do tmp := names[1]; names[1] := names[index]; names[index] := tmp; recursive(names, 2); names[index] := names[1]; names[1] := tmp; end for; writeln("maximum path length: " <& maxPathLength lpad 4); writeln("paths of that length: " <& maxPathLengthCount lpad 4); writeln("example path of that length:" <& maxPathExample); end func;</syntaxhighlight> Output: <pre> maximum path length: 23 paths of that length: 1248 example path of that length: machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> =={{header\|Sidef}}== {{trans\|Perl}} <syntaxhighlight lang="ruby">class LLFL(Array words) { has f = Hash() method init { words.each {\|w\| var m = w.match(/^(.).*(.)$/) f{m[0]}{w} = m[1] } } method longest_chain { var stack = [] var longest = [] func poke(c) { var h = f{c} h.each_k { \|word\| var v = h.delete(word) stack.push(word) longest[] = stack[] if (stack.len > longest.len) __FUNC__(v) if f.exists(v) stack.pop h{word} = v } } f.each_k { poke(_) } return longest } } var words = %w( audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon cresselia croagunk darmanitan deino emboar emolga exeggcute gabite girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask ) var obj = LLFL(words) var longest = obj.longest_chain() say "#{longest.len}: #{longest.join(' ')}"</syntaxhighlight> {{out}} <pre> 23: machamp petilil landorus scrafty yamask kricketune exeggcute emboar registeel loudred darmanitan nosepass simisear rufflet trapinch heatmor relicanth haxorus seaking girafarig gabite emolga audino </pre> =={{header\|Tcl}}== <~~lang~~syntaxhighlight lang="tcl">proc search {path arcs} { set solutions {} set c [string index [lindex $path end] end] Line 1,281 ⟶ 4,946: } set path [firstlast $names] puts "Path (length: [llength $path]): $path"</~~lang~~syntaxhighlight> Output: <pre> Line 1,289 ⟶ 4,954: =={{header\|Ursala}}== <~~lang~~syntaxhighlight ~~Ursala~~lang="ursala">#import std mon = Line 1,307 ⟶ 4,972: #show+ example = ~&h poke mon</~~lang~~syntaxhighlight>output: <pre>machamp petilil Line 1,331 ⟶ 4,996: emolga audino </pre> =={{header\|VBScript}}== {{trans\|BBC BASIC}} <syntaxhighlight lang="vb">' Last letter-first letter - VBScript - 11/03/2019 names = array( _ "audino", "bagon", "baltoy", "banette", _ "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", _ "cresselia", "croagunk", "darmanitan", "deino", "emboar", _ "emolga", "exeggcute", "gabite", "girafarig", "gulpin", _ "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", _ "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", _ "loudred", "lumineon", "lunatone", "machamp", "magnezone", _ "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", _ "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", _ "registeel", "relicanth", "remoraid", "rufflet", "sableye", _ "scolipede", "scrafty", "seaking", "sealeo", "silcoon", _ "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", _ "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", _ "wailord", "wartortle", "whismur", "wingull", "yamask") maxPathLength = 0 maxPathLengthCount = 0 maxPathExample = "" t1=timer For i = 0 To ubound(names) 'swap names(0), names(i) temp=names(0): names(0)=names(i): names(i)=temp Call lastfirst(names, 1) 'swap names(0), names(i) temp=names(0): names(0)=names(i): names(i)=temp Next 'i buf = buf & "Maximum length = " & maxPathLength & vbCrLf buf = buf & "Number of solutions with that length = " & maxPathLengthCount & vbCrLf buf = buf & "One such solution: " & vbCrLf & maxPathExample & vbCrLf t2=timer MsgBox buf,,"Last letter-first letter - " & Int(t2-t1) & " sec" Sub lastfirst(names, offset) dim i, l If offset > maxPathLength Then maxPathLength = offset maxPathLengthCount = 1 ElseIf offset = maxPathLength Then maxPathLengthCount = maxPathLengthCount + 1 maxPathExample = "" For i = 0 To offset-1 maxPathExample = maxPathExample & names(i) & vbCrLf Next 'i End If l = Right(names(offset - 1),1) For i = offset To ubound(names) If Left(names(i),1) = l Then 'swap names(i), names(offset) temp=names(offset): names(offset)=names(i): names(i)=temp Call lastfirst(names, offset+1) 'swap names(i), names(offset) temp=names(offset): names(offset)=names(i): names(i)=temp End If Next 'i End Sub 'lastfirst </syntaxhighlight> {{out}} <pre> Maximum length = 23 Number of solutions with that length = 1248 One such solution: machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> Duration : 69 sec =={{header\|Wren}}== {{trans\|Kotlin}} <syntaxhighlight lang="wren">var maxPathLength = 0 var maxPathLengthCount = 0 var maxPathExample = "" var names = [ "audino", "bagon", "baltoy", "banette", "bidoof", "braviary", "bronzor", "carracosta", "charmeleon", "cresselia", "croagunk", "darmanitan", "deino", "emboar", "emolga", "exeggcute", "gabite", "girafarig", "gulpin", "haxorus", "heatmor", "heatran", "ivysaur", "jellicent", "jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba", "loudred", "lumineon", "lunatone", "machamp", "magnezone", "mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu", "pinsir", "poliwrath", "poochyena", "porygon2", "porygonz", "registeel", "relicanth", "remoraid", "rufflet", "sableye", "scolipede", "scrafty", "seaking", "sealeo", "silcoon", "simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga", "trapinch", "treecko", "tyrogue", "vigoroth", "vulpix", "wailord", "wartortle", "whismur", "wingull", "yamask" ] var search // recursive function search = Fn.new { \|part, offset\| if (offset > maxPathLength) { maxPathLength = offset maxPathLengthCount = 1 } else if (offset == maxPathLength) { maxPathLengthCount = maxPathLengthCount + 1 maxPathExample = "" for (i in 0...offset) { maxPathExample = maxPathExample + ((i % 5 == 0) ? "\n " : " ") + part[i] } } var lastChar = part[offset - 1][-1] for (i in offset...part.count) { if (part[i][0] == lastChar) { var tmp = names[offset] names[offset] = names[i] names[i] = tmp search.call(names, offset + 1) names[i] = names[offset] names[offset] = tmp } } } for (i in 0...names.count) { var tmp = names[0] names[0] = names[i] names[i] = tmp search.call(names, 1) names[i] = names[0] names[0] = tmp } System.print("Maximum path length : %(maxPathLength)") System.print("Paths of that length : %(maxPathLengthCount)") System.print("Example path of that length : %(maxPathExample)")</syntaxhighlight> {{out}} <pre> Maximum path length : 23 Paths of that length : 1248 Example path of that length : machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino </pre> =={{header\|Yabasic}}== {{trans\|Phix}} <syntaxhighlight lang="yabasic">all$ = "audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon " all$ = all$ + "cresselia croagunk darmanitan deino emboar emolga exeggcute gabite " all$ = all$ + "girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan " all$ = all$ + "kricketune landorus ledyba loudred lumineon lunatone machamp magnezone mamoswine " all$ = all$ + "nosepass petilil pidgeotto pikachu pinsir poliwrath poochyena porygon2 " all$ = all$ + "porygonz registeel relicanth remoraid rufflet sableye scolipede scrafty seaking " all$ = all$ + "sealeo silcoon simisear snivy snorlax spoink starly tirtouga trapinch treecko " all$ = all$ + "tyrogue vigoroth vulpix wailord wartortle whismur wingull yamask" dim word$(1) lnames = token(all$, word$()) dim first(256), snext(lnames) for i = 1 to lnames ch = asc(left$(word$(i), 1)) if first(ch)=0 then first(ch) = i end if for j=i+1 to lnames if asc(left$(word$(j), 1))=ch then snext(i) = j break end if next next dim taken(lnames), best(lnames) sub try(ch, last, n) local nex, i nex = first(ch) while(nex <> 0) if taken(nex)=0 then taken(last) = nex taken(nex) = -1 try(asc(right$(word$(nex), 1)),nex,n+1) taken(last) = -1 taken(nex) = 0 end if nex = snext(nex) wend if n>maxn then bstart = tstart for i = 1 to lnames best(i) = taken(i) next maxn = n count = 1 elsif n=maxn then count = count + 1 end if end sub for i=1 to lnames tstart = i taken(i) = -1 try(asc(right$(word$(i), 1)),i,1) taken(i) = 0 next print "Runtime: ", peek("millisrunning")/1000, " seconds. Max length: ", maxn, ", found ", count, " of such, one of which is:\n" do print word$(bstart), " "; bstart = best(bstart) if bstart = -1 break loop</syntaxhighlight> =={{header\|zkl}}== This solution creates a hash table to all the possible word/following words to minimize search times. No speed records were approached but 25sec seems fine for a one off walk the entire tree. <syntaxhighlight lang="zkl">pokemon:=("audino bagon baltoy banette bidoof braviary " "bronzor carracosta charmeleon cresselia croagunk darmanitan deino " ... "whismur wingull yamask").split(); tree:=pokemon.pump(Dictionary(),'wrap(name){ //--> Hash("aB":("Bc","Bd",,,) ) T( name, pokemon.filter('wrap(nm){ name[-1]==nm[0] }) ) }); fcn maxPath([(a,_)]ab,[(c,_)]cd){ if(a>c) ab else cd } fcn walk(name,pathLen,path,tree){ //-->longest path for name names:=tree.find(name,T); tree[name]=T; // nuke cycle np:=names.reduce('wrap(np,name){ maxPath(np,walk(name,pathLen+1,String(path," ",name),tree)); },T(0,"")); tree[name]=names; if(np[0]>pathLen) return(np); return(pathLen,path); } pokemon.reduce('wrap(np,name){ maxPath(walk(name,1,name,tree),np) },T(0,"")) .println();</syntaxhighlight> {{out}} <pre> L(23,"machamp pinsir rufflet trapinch heatmor remoraid darmanitan nosepass starly yamask kricketune exeggcute emboar relicanth haxorus simisear registeel landorus seaking girafarig gabite emolga audino") </pre>